A novel epoxidized soybean oil-toughened-phenolic resin(ESO-T-PR)has been synthesized by etheri- fication graft and multi-amine curing ESO.Fourier transform infrared spectroscopy(FTIR)was adopted to investi- gate its ...A novel epoxidized soybean oil-toughened-phenolic resin(ESO-T-PR)has been synthesized by etheri- fication graft and multi-amine curing ESO.Fourier transform infrared spectroscopy(FTIR)was adopted to investi- gate its molecular structure and scan electron microscope(SEM)was used to observe the micro morphology of its impact fracture surface.This ESO-T-PR was adopted as the matrix resin to prepare paper copper clad laminate (P-CCL)and the properties of resulting P-CCL are found superior to the related Chinese National Standard.The toughing mechanism was investigated by comparing the impact strength,solderleaching resistance,flexural strength, peeling strength and morphology of this ESO-T-PR with those of other two ESO modified phenolic resins.It is demonstrated that during the synthesizing process of ESO-T-PR,the phenol hydroxyl is etherified by ESO or ESO epoxy resin prepolymer(ESO chain extension polymer)and the long ESO epoxy resin chain segments enhance the crosslink density of ESO-T-PR and consequently improve the impact toughness and solderleaching resistance of P-CCL made of ESO-T-PR.The ESO-T-PR is a cheap matrix resin with excellent properties to make P-CCL(elec- tric guide board).展开更多
Currently adopted cross-linking methods in rubber industry are suffering from variable persistent issues, including the utilization of toxic curing packages, release of volatile organic compounds (VOCs) and difficulti...Currently adopted cross-linking methods in rubber industry are suffering from variable persistent issues, including the utilization of toxic curing packages, release of volatile organic compounds (VOCs) and difficulties in the recycling of end-of-life materials. It is of great importance to explore a green cross-linking strategy in the area. Herein, we report a new ‘‘green" strategy based on hydrolyzable ester cross-links for cross-linking diene-typed elastomers. As a proof of concept, a commercial carboxylated nitrile rubber (XNBR) is efficiently cross-linked by a bio-based agent, epoxidized soybean oil (ESO), without any toxic additives. ESO exhibits an excellent plasticization effect and excellent scorch safety for XNBR. The crosslinking density and mechanical properties of the ESO-cured XNBR can be manipulated in a wide range by changing simply varying the content of ESO. In addition, zinc oxide (Zn O) performs as a catalyst to accelerate the epoxide opening reaction and improve the cross-linking efficiency, serving as reinforcement points to enhance the overall mechanical properties of the ESO-cured XNBR. Furthermore, the end-oflife elastomer materials demonstrate a closed-loop recovery by selectively cleaving the ester bonds, resulting in very high recovery of the mechanical performance of the recycled composites. This strategy provides an unprecedented green avenue to cross-link diene elastomers and a cost-effective approach to further recycle the obtained cross-linked elastomers at high efficiency.展开更多
Electromagnetic interference(EMI)and radiation of electronic devices are ubiquitous,which are potentially hazardous to the normal operation of electronic equipment and human health.MXenes are extremely attractive in t...Electromagnetic interference(EMI)and radiation of electronic devices are ubiquitous,which are potentially hazardous to the normal operation of electronic equipment and human health.MXenes are extremely attractive in the preparation of EMI shielding materials due to their excellent metallic conductivity and tunable surface chemistry.Herein,by virtue of the designed nanostructure and regulation of interface interactions,we fabricated flexible Fe_(3)O_(4)@Ti_(3)C_(2)Tx MXene/3,4-dihydroxyphenylacetic acid(DOPAC)-epoxidized natural rubber(ENR)elastomers(FMDE)with 3D segregated interconnected structures.The elaborately designed metalligand coordination crosslinking between Fe_(3)O_(4)nanoparticles and DOPAC ligand molecules provides strong interfacial interactions,resulting in significantly reinforced mechanical properties.Compared with Ti_(3)C_(2)Tx/ENR elastomers,the maximum tensile strength and toughness of FMDE are elevadted by~306%and 475%,respectively.Moreover,the 3D segregated conductive network constructed by Fe_(3)O_(4)@Ti_(3)C_(2)Tx nanoflakes resulted from volume exclusion effect of ENR latex and the introduction of magnetic Fe_(3)O_(4)nanoparticles with enhanced electromagnetic wave absorption greatly improved the EMI shielding performance of FMDE,exhibiting an excellent EMI shielding effectiveness of up to 58 dB in the X band(8.2–12.4 GHz)and stable EMI shielding capability during repeated deformations.This work provides a promising strategy for the design and manufacture of novel flexible EMI shielding materials.展开更多
The aim of this research work was to evaluate the potential of using renewable natural feedstock,i.e.,Jatropha curcas oil(JCO)for the synthesis of non-isocyanate polyurethane(NIPU)resin for wood composite applications...The aim of this research work was to evaluate the potential of using renewable natural feedstock,i.e.,Jatropha curcas oil(JCO)for the synthesis of non-isocyanate polyurethane(NIPU)resin for wood composite applications.Commercial polyurethane(PU)is synthesized through a polycondensation reaction between isocyanate and poly-ol.However,utilizing toxic and unsustainable isocyanates for obtaining PU could contribute to negative impacts on the environment and human health.Therefore,the development of PU from eco-friendly and sustainable resources without the isocyanate route is required.In this work,tetra-n-butyl ammonium bromide was used as the activator to open the epoxy ring with 3-Aminopropyltriethoxisylane as a catalyst to yield urethane of JCO(UJCO).The UJCO were characterized by Fourier Transform Infra-Red spectroscopy(FTIR)and their oxirane,and hydroxyl values were measured.The result showed that a decrease in oxirane value was found while the hydroxyl value was increased during the time,confirming that the urethane group was formed.The presence of functional groups in FTIR spectra at wave numbers 1732.08,1562.34,and 3348.42 cm^(−1) indicates the functional groups of C=O(urethane carbonyl),–NH,and–OH,respectively confirmed this finding.The potential applications of NIPU in the wood composite were also outlined.展开更多
This study investigated that epoxidized soybean oil （ESO） was blended as plasticizer with poly （lactic acid） （PLA） and its effects on the melt rheological properties, such as melt flow index, apparent shear visc...This study investigated that epoxidized soybean oil （ESO） was blended as plasticizer with poly （lactic acid） （PLA） and its effects on the melt rheological properties, such as melt flow index, apparent shear viscosity, and melt strength of the blends. PLA was blended by the twin-screw plastic extruder at five mass fractions： 3%, 6%, 9%, 12%, and 15% （based on PLA mass）. Melt flow index （MFI） was examined with a melt flow indexer. The results indicate that the blends of PLA/ESO had higher MFI than pure PLA, except for MFI at 9% reaching to the lowest point, even lower than that of pure PLA. Melt rheological properties were studied by a capillary rheometer in a temperature range of 160-180℃. The blends exhibited shear-thinning behavior and the apparent shear viscosity was well described by the power law in this shear rate region. The melt strength of PLA plasticized with 6% ESO reached the maximums. ESO was more effective in increasing the melt strength at the mass fractions less than 6%, which could toughen the blends to some extent. Therefore, the authors suggested the optimum addition level of 6%-9% ESO will get good melt rheological performance balance.展开更多
Processing polyvinyl chloride(PVC)artificial material requires plasticizer that softens the PVC coating.Currently,utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester(EFAME)bio-p...Processing polyvinyl chloride(PVC)artificial material requires plasticizer that softens the PVC coating.Currently,utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester(EFAME)bio-plasticizers constitutes an environmentally responsible solution to substitute conventional ortho-phthalates that are endocrine disruptors or probable carcinogens.However,commercial EFAMEs,even with the highest epoxy value(ca.5.5-5.8%)so far,still suffer from fast leaching from the PVC matrix,burdening the environment and shortening lifespan of the artificial material.Here,we report a proof-of-principle demonstration of a new strategy to obtain migration-resistant EFAME that harnesses the midchain hydroxyl of methyl ricinoleate and covalently attachment of a pendant acetate ester.Despite a low epoxy value(3.0%),the engineered bio-plasticizer displays significantly suppressed migration in multiple scenarios compared with one conventional EFAME with much higher epoxy value(5.8%).Circumventing the limit confronting previous strategy that highlights the sole contribution of epoxy value to achievable migration resistance,the rationale herein may provide guidance for designing new EFAMEs with comparable performance to ortho-phthalates,thus bringing the old and oft-maligned PVC artificial material industry one step closer to sustainability.展开更多
The novel epoxidized soybean oil-modified-phenolic resin/clay nanocomposites（ESO-M-PR/ CN） was prepared. The coupling agent-benzyldimethylphenylammonium chloride [C6H5CH2N^＋（CH3）2C6H5Cl^- , B2MP] was adopted to m...The novel epoxidized soybean oil-modified-phenolic resin/clay nanocomposites（ESO-M-PR/ CN） was prepared. The coupling agent-benzyldimethylphenylammonium chloride [C6H5CH2N^＋（CH3）2C6H5Cl^- , B2MP] was adopted to modify the interface between the organic and inorganic phases. The effect of the nanocomposite structure on its physical and chemical properties was discussed. During the synthesizing process of ESO-M-PR/CN, the phenol hydroxyl was etherified by ESO or ESO epoxy resin prepolymer to provide long ESO epoxy segments. Long ESO epoxy resin chain segments enhanced the crosslink density of ESO-M- PR/CN. The thermal and mechanical properties exhibit a significant improvement. The temperature at which a weight loss of 5% occurs increases from 287.1 ℃ to 402.3 ℃. The flexural strength increases by 25%, while the flexural modulus increases by 39%. Moreover, the properties of resin were enhanced by the effect of the inorganic nanoparticles, while the size of the nanomontmorillonites in the phenolic resin was characterized with a scanning electron microscope. The particle size of inorganic montmorillonites in the modified system is less than 100 nm.展开更多
Here,we report the mechanical and water sorption properties of a green composite based on Typha latifolia fibres.The composite was prepared either completely binder-less or bonded with 10%(w/w)of a bio-based resin whi...Here,we report the mechanical and water sorption properties of a green composite based on Typha latifolia fibres.The composite was prepared either completely binder-less or bonded with 10%(w/w)of a bio-based resin which was a mixture of an epoxidized linseed oil and a tall-oil based polyamide.The flexural modulus of elasticity,the flexural strength and the water absorption of hot pressed Typha panels were measured and the influence of pressing time and panel density on these properties was investigated.The cure kinetics of the biobased resin was analyzed by differential scanning calorimetry(DSC)in combination with the iso-conversional kinetic analysis method of Vyazovkin to derive the curing conditions required for achieving completely cured resin.For the binderless Typha panels the best technological properties were achieved for panels with high density.By adding 10%of the binder resin the flexural strength and especially the water absorption were improved significantly.展开更多
The natural rubber (NR) was mixed with chlorosulfonated polyethylene (CSM), due to the difference of polarity in NR and CSM made this blend incompatible and the third component was used. Epoxidzed natural rubber (ENR)...The natural rubber (NR) was mixed with chlorosulfonated polyethylene (CSM), due to the difference of polarity in NR and CSM made this blend incompatible and the third component was used. Epoxidzed natural rubber (ENR) was used as a third component. NR/CSM blended with the blend ratio of 50/50 was prepared by using a two-roll mill and vulcanization in a compression mold at 160°C. The ENR content was varied from 1 to 7 phr. The curing characteristics, morphology, mechanical properties, and automotive fuel swelling were investigated. The results indicated that the cure time of the blend rubbers was shorter as adding ENR. The mechanical properties of the blend rubbers were not affected by ENR content. However, automotive fuel resistance of the blend rubbers was found to increase with adding ENR in rubber blend.展开更多
Dehydrated castor oil was epoxidized using phosphoric acid as a catalyst and acetic acid peroxide as an oxidant to produce epoxidized castor oil(ECO). Ringopening polymerization with stannic chloride was used to produ...Dehydrated castor oil was epoxidized using phosphoric acid as a catalyst and acetic acid peroxide as an oxidant to produce epoxidized castor oil(ECO). Ringopening polymerization with stannic chloride was used to produce polymerized ECO(PECO), and sodium hydroxide used to give hydrolyzed PECO(HPECO). The HPECO was characterized by Fourier transform infrared,1H and13 Cnuclear magnetic resonance spectroscopies,gel permeation chromatography, and differential scanning calorimetry. The weight-average molecular weight of soluble PECO and HPECO were 5026 and2274 g$mol^(–1), respectively. PECO and HPECO exhibited glass transition. Through neutralizing the carboxylic acid of HPECO with different counterions, castor oil-based polymeric surfactants(HPECO-M, where M = Na^+, K^+or triethanolamine ion) exhibited high ef ficiency to reduce the surface tension of water. The critical micelle concentration(CMC) values of HPECO-M ranged from0.042 to 0.098 g$L^(–1)and the minimum equilibrium surface tensions at CMC(g cmc) of HPECO-M ranged from 25.6 to30.0 m N$m^(–1). The water-hexadecane interfacial energy was calculated from measured surface tension using harmonic and geometric mean methods. Measured values of water-hexadecane interfacial tension agreed well with those calculated using the harmonic and geometric mean methods.展开更多
This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (S...This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). SEM images showed the reduction in fiber size with ENR content of up to 25% in the mixture PLA/ENR. FTIR analysis revealed a possible interaction between carboxylic group of PLA and epoxi group of ENR. Thermal analysis showed the increase of the crystallinity fraction with ENR content and a decrease in thermal stability of eletrospun mats with the addition of ENR. The dynamic mechanical properties showed an enhancement of the stiffness of PLA/ENR blends with the increase of ENR content, which can support the production of interesting materials for tissue engineering based on renewable and biocompatible polymers. The reported properties indicate the possibility to use such fiber mats as potential materials in tissue engineering.展开更多
The natural rubber (NR) was mixed with fluoro elastomer (FKM), due to the difference of polarity in NR and FKM made this blend incompatible so the third component was used. NR/FKM blended with the blend ratio of 70/30...The natural rubber (NR) was mixed with fluoro elastomer (FKM), due to the difference of polarity in NR and FKM made this blend incompatible so the third component was used. NR/FKM blended with the blend ratio of 70/30 was prepared by using a two-roll mill and vulcanization in a compression mold at 180℃ using peroxide as a curative agent. Epoxidized natural rubber (ENR) or polyisoprene-graft-maleic acid monomethyl ester (PI-ME) was used as a third component. The curing characteristics, morphology, mechanical properties, and automotive fuel swelling were investigated. The results indicated that the scorch time and cure time of the blend rubbers were longer as adding ENR or PI-ME. Both mechanical properties and automotive fuel resistance of the blend rubbers were found to increase with adding ENR in rubber blend. Conversely for adding PI-ME, automotive fuel resistance of the blend rubbers was found to decrease progressively with increasing PI-ME content.展开更多
Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface....Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable sources in the manufacture of rubber products. The aim of this work is to investigate the possibilities of using elastomers and ingredients from renewable sources—epoxidized natural rubber, silica obtained by rice husks incineration and microcrystalline cellulose—as fillers and rapeseed oil as a process additive in compositions, intended for the manufacture of soles for winter footwear having an increased coefficient of friction to icy surfaces. The tribological tests based on the coefficient of friction evaluated the adhesion of the composites to the icy surfaces at different temperatures. The complex evaluation of developed composites revealed those containing microcrystalline cellulose and biogenic amorphous silica at a 1:1 ratio as the most suitable for making footwear soles because of the best combination of physicо-mechanical properties and coefficient of friction.展开更多
In this work, polyester polyols with high weight average molecular weight （Mw） （Mw= 10000-15000） were prepared from epoxidized palm olein （EPOo） and a series of dicarboxylic acids （C6-C12） at elevated temperat...In this work, polyester polyols with high weight average molecular weight （Mw） （Mw= 10000-15000） were prepared from epoxidized palm olein （EPOo） and a series of dicarboxylic acids （C6-C12） at elevated temperature under non-catalyzed condition. The optimal reaction conditions were determined as 180 ℃ for 4 h. Longer carbon chain length of dicarboxylic acids was more reactive when reacted with EPOo. The physical appearance of the product was observed as liquid at room temperature. This palm oil-based polyester polyol is proposed as starting material for flexible polyurethane. For reaction monitoring purposes, FTIR was used while 1H NMR analysis was carried out to characterize the important functional groups of the products. The effects of reaction time and temperature on the Mw of the reaction mixture were also studied by GPC.展开更多
A novel phosphorous-containing acrylated epoxidized soybean oil-based(P-AESO)resin was developed via the ring-opening reaction of epoxidized soybean oil(ESO)with diphenylphosphinic chloride(DPPC),followed by acrylatio...A novel phosphorous-containing acrylated epoxidized soybean oil-based(P-AESO)resin was developed via the ring-opening reaction of epoxidized soybean oil(ESO)with diphenylphosphinic chloride(DPPC),followed by acrylation of the resulting groups.The chemical structure was characterized by Fourier transform infrared spectroscopy(FT-IR),and ^(1)H nuclear magnetic resonance(^(1)H NMR).Subsequently,the viscosity and volumetric shrinkage of the obtained P-AESO resins were studied.Then the oligomer was formulated into UV-curable coatings,and the mechanical,thermal,and coating properties of the resulting UV-cured bioresins were studied by tensile testing,dynamic mechanical thermal analysis(DMA),thermogravimetric analysis(TGA)coupled with FT-IR spectroscopy(TGA-FT-IR),hardness,adhesion,pencil hardness and chemical resistance.Furthermore,the UV-curing behavior of the P-AESO resin was determined by real-time realtime infrared(RT-IR).Meanwhile,compared with coating from acrylated epoxidized soybean oil(AESO),the P-AESO system coatings showed better volumetric shrinkage,excellent adhesion,and enhanced thermal and glass transition temperature(Tg)while maintaining reasonably final C=C conversions and cross-link density.For instance,the obtained P-AESO/trimethylolpropanetriacrylate(TMPTA)20 material possessed a volumetric shrinkage of 4.1%,Tg of 115.6℃,char yield of 9.47%,and final C=C conversions of 81.4%respectively,which exhibited superior values than that of the AESO/TMPTA20 material.The improvement of the P-AESO coating performances could contribute to the architectures that combined the structural features of phosphorous-containing rigid benzene.The developed P-AESO resin is promising for applications in the UV-curable coatings.展开更多
A novel kind of fully bio-based PSAs we re obtained through the curing reaction between two components derived from the plant oils:carboxyl-terminated polyricinoleate(PRA) fro m the castor oil and epoxidized soybean o...A novel kind of fully bio-based PSAs we re obtained through the curing reaction between two components derived from the plant oils:carboxyl-terminated polyricinoleate(PRA) fro m the castor oil and epoxidized soybean oil(ESO).The get content,glass transition temperature(Tg),rheological behavior,tensile strength,creep resistance and 180° peel strength of the PSAs were feasibly tailored by adjusting the component ratio of ESO to PRA.At low cross-linking level,the PSAs behaved like a viscous liquid and did not possess enough cohesiveness to sustain the mechanical stress during peeling,The PSAs cross-linked at or near the optimal stoichiometric conditions displayed an adhesive(interfacial) failure between the substrate and the adhesive layer,which were associated with the lowest adhesion levels.The PSAs with the dosage amount of ESO ranging from 10.20 wt% were tacky and flexible,which exhibited 1800 peel strength ranging from 0.4~2.3 N/cm;and could be easily removed without any residues on the adherend.The process for the preparation of the fully bio-based PSAs was environmentally friendly without using any orga nic solve nt or other toxic chemical,herein showing the great potential as sustainable materials.展开更多
基金Supported by the Key Science&Technology Item of Guangdong Province(TC05B372-6).
文摘A novel epoxidized soybean oil-toughened-phenolic resin(ESO-T-PR)has been synthesized by etheri- fication graft and multi-amine curing ESO.Fourier transform infrared spectroscopy(FTIR)was adopted to investi- gate its molecular structure and scan electron microscope(SEM)was used to observe the micro morphology of its impact fracture surface.This ESO-T-PR was adopted as the matrix resin to prepare paper copper clad laminate (P-CCL)and the properties of resulting P-CCL are found superior to the related Chinese National Standard.The toughing mechanism was investigated by comparing the impact strength,solderleaching resistance,flexural strength, peeling strength and morphology of this ESO-T-PR with those of other two ESO modified phenolic resins.It is demonstrated that during the synthesizing process of ESO-T-PR,the phenol hydroxyl is etherified by ESO or ESO epoxy resin prepolymer(ESO chain extension polymer)and the long ESO epoxy resin chain segments enhance the crosslink density of ESO-T-PR and consequently improve the impact toughness and solderleaching resistance of P-CCL made of ESO-T-PR.The ESO-T-PR is a cheap matrix resin with excellent properties to make P-CCL(elec- tric guide board).
基金This work was supported by the National Natural Science Foundation of China(NSFC,51790501 and 51825303),the Basic Science Center Program of NSFC(51988102)the National Key Research and Development Program of China(2017YFB0306900 and 2017YFB0306904)the Beijing Advanced Innovation Center for Soft Matter Science and Engineering
文摘Currently adopted cross-linking methods in rubber industry are suffering from variable persistent issues, including the utilization of toxic curing packages, release of volatile organic compounds (VOCs) and difficulties in the recycling of end-of-life materials. It is of great importance to explore a green cross-linking strategy in the area. Herein, we report a new ‘‘green" strategy based on hydrolyzable ester cross-links for cross-linking diene-typed elastomers. As a proof of concept, a commercial carboxylated nitrile rubber (XNBR) is efficiently cross-linked by a bio-based agent, epoxidized soybean oil (ESO), without any toxic additives. ESO exhibits an excellent plasticization effect and excellent scorch safety for XNBR. The crosslinking density and mechanical properties of the ESO-cured XNBR can be manipulated in a wide range by changing simply varying the content of ESO. In addition, zinc oxide (Zn O) performs as a catalyst to accelerate the epoxide opening reaction and improve the cross-linking efficiency, serving as reinforcement points to enhance the overall mechanical properties of the ESO-cured XNBR. Furthermore, the end-oflife elastomer materials demonstrate a closed-loop recovery by selectively cleaving the ester bonds, resulting in very high recovery of the mechanical performance of the recycled composites. This strategy provides an unprecedented green avenue to cross-link diene elastomers and a cost-effective approach to further recycle the obtained cross-linked elastomers at high efficiency.
基金supported by the National Natural Science Foundation of China (51861165203)China Postdoctoral Science Foundation (2019M653398)+1 种基金Sichuan Science and Technology Program (2020YJ0261)Shiyanjia Lab (www.shiyanjia.com) for the support of VSM and XRD test
文摘Electromagnetic interference(EMI)and radiation of electronic devices are ubiquitous,which are potentially hazardous to the normal operation of electronic equipment and human health.MXenes are extremely attractive in the preparation of EMI shielding materials due to their excellent metallic conductivity and tunable surface chemistry.Herein,by virtue of the designed nanostructure and regulation of interface interactions,we fabricated flexible Fe_(3)O_(4)@Ti_(3)C_(2)Tx MXene/3,4-dihydroxyphenylacetic acid(DOPAC)-epoxidized natural rubber(ENR)elastomers(FMDE)with 3D segregated interconnected structures.The elaborately designed metalligand coordination crosslinking between Fe_(3)O_(4)nanoparticles and DOPAC ligand molecules provides strong interfacial interactions,resulting in significantly reinforced mechanical properties.Compared with Ti_(3)C_(2)Tx/ENR elastomers,the maximum tensile strength and toughness of FMDE are elevadted by~306%and 475%,respectively.Moreover,the 3D segregated conductive network constructed by Fe_(3)O_(4)@Ti_(3)C_(2)Tx nanoflakes resulted from volume exclusion effect of ENR latex and the introduction of magnetic Fe_(3)O_(4)nanoparticles with enhanced electromagnetic wave absorption greatly improved the EMI shielding performance of FMDE,exhibiting an excellent EMI shielding effectiveness of up to 58 dB in the X band(8.2–12.4 GHz)and stable EMI shielding capability during repeated deformations.This work provides a promising strategy for the design and manufacture of novel flexible EMI shielding materials.
文摘The aim of this research work was to evaluate the potential of using renewable natural feedstock,i.e.,Jatropha curcas oil(JCO)for the synthesis of non-isocyanate polyurethane(NIPU)resin for wood composite applications.Commercial polyurethane(PU)is synthesized through a polycondensation reaction between isocyanate and poly-ol.However,utilizing toxic and unsustainable isocyanates for obtaining PU could contribute to negative impacts on the environment and human health.Therefore,the development of PU from eco-friendly and sustainable resources without the isocyanate route is required.In this work,tetra-n-butyl ammonium bromide was used as the activator to open the epoxy ring with 3-Aminopropyltriethoxisylane as a catalyst to yield urethane of JCO(UJCO).The UJCO were characterized by Fourier Transform Infra-Red spectroscopy(FTIR)and their oxirane,and hydroxyl values were measured.The result showed that a decrease in oxirane value was found while the hydroxyl value was increased during the time,confirming that the urethane group was formed.The presence of functional groups in FTIR spectra at wave numbers 1732.08,1562.34,and 3348.42 cm^(−1) indicates the functional groups of C=O(urethane carbonyl),–NH,and–OH,respectively confirmed this finding.The potential applications of NIPU in the wood composite were also outlined.
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (20030561014)
文摘This study investigated that epoxidized soybean oil （ESO） was blended as plasticizer with poly （lactic acid） （PLA） and its effects on the melt rheological properties, such as melt flow index, apparent shear viscosity, and melt strength of the blends. PLA was blended by the twin-screw plastic extruder at five mass fractions： 3%, 6%, 9%, 12%, and 15% （based on PLA mass）. Melt flow index （MFI） was examined with a melt flow indexer. The results indicate that the blends of PLA/ESO had higher MFI than pure PLA, except for MFI at 9% reaching to the lowest point, even lower than that of pure PLA. Melt rheological properties were studied by a capillary rheometer in a temperature range of 160-180℃. The blends exhibited shear-thinning behavior and the apparent shear viscosity was well described by the power law in this shear rate region. The melt strength of PLA plasticized with 6% ESO reached the maximums. ESO was more effective in increasing the melt strength at the mass fractions less than 6%, which could toughen the blends to some extent. Therefore, the authors suggested the optimum addition level of 6%-9% ESO will get good melt rheological performance balance.
基金financial support of this work by National Key Research and Development Program of China(2017YFB0308600)National Natural Science Foundation of China(21878196)Fundamental Research Funds for the Central Universities,China(20826041C4159).
文摘Processing polyvinyl chloride(PVC)artificial material requires plasticizer that softens the PVC coating.Currently,utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester(EFAME)bio-plasticizers constitutes an environmentally responsible solution to substitute conventional ortho-phthalates that are endocrine disruptors or probable carcinogens.However,commercial EFAMEs,even with the highest epoxy value(ca.5.5-5.8%)so far,still suffer from fast leaching from the PVC matrix,burdening the environment and shortening lifespan of the artificial material.Here,we report a proof-of-principle demonstration of a new strategy to obtain migration-resistant EFAME that harnesses the midchain hydroxyl of methyl ricinoleate and covalently attachment of a pendant acetate ester.Despite a low epoxy value(3.0%),the engineered bio-plasticizer displays significantly suppressed migration in multiple scenarios compared with one conventional EFAME with much higher epoxy value(5.8%).Circumventing the limit confronting previous strategy that highlights the sole contribution of epoxy value to achievable migration resistance,the rationale herein may provide guidance for designing new EFAMEs with comparable performance to ortho-phthalates,thus bringing the old and oft-maligned PVC artificial material industry one step closer to sustainability.
基金the Key Science & Technology Item of Guangdong province (No. TC05B372-6)
文摘The novel epoxidized soybean oil-modified-phenolic resin/clay nanocomposites（ESO-M-PR/ CN） was prepared. The coupling agent-benzyldimethylphenylammonium chloride [C6H5CH2N^＋（CH3）2C6H5Cl^- , B2MP] was adopted to modify the interface between the organic and inorganic phases. The effect of the nanocomposite structure on its physical and chemical properties was discussed. During the synthesizing process of ESO-M-PR/CN, the phenol hydroxyl was etherified by ESO or ESO epoxy resin prepolymer to provide long ESO epoxy segments. Long ESO epoxy resin chain segments enhanced the crosslink density of ESO-M- PR/CN. The thermal and mechanical properties exhibit a significant improvement. The temperature at which a weight loss of 5% occurs increases from 287.1 ℃ to 402.3 ℃. The flexural strength increases by 25%, while the flexural modulus increases by 39%. Moreover, the properties of resin were enhanced by the effect of the inorganic nanoparticles, while the size of the nanomontmorillonites in the phenolic resin was characterized with a scanning electron microscope. The particle size of inorganic montmorillonites in the modified system is less than 100 nm.
基金funding and support from the Austrian Research Promotion Agency(FFG).
文摘Here,we report the mechanical and water sorption properties of a green composite based on Typha latifolia fibres.The composite was prepared either completely binder-less or bonded with 10%(w/w)of a bio-based resin which was a mixture of an epoxidized linseed oil and a tall-oil based polyamide.The flexural modulus of elasticity,the flexural strength and the water absorption of hot pressed Typha panels were measured and the influence of pressing time and panel density on these properties was investigated.The cure kinetics of the biobased resin was analyzed by differential scanning calorimetry(DSC)in combination with the iso-conversional kinetic analysis method of Vyazovkin to derive the curing conditions required for achieving completely cured resin.For the binderless Typha panels the best technological properties were achieved for panels with high density.By adding 10%of the binder resin the flexural strength and especially the water absorption were improved significantly.
文摘The natural rubber (NR) was mixed with chlorosulfonated polyethylene (CSM), due to the difference of polarity in NR and CSM made this blend incompatible and the third component was used. Epoxidzed natural rubber (ENR) was used as a third component. NR/CSM blended with the blend ratio of 50/50 was prepared by using a two-roll mill and vulcanization in a compression mold at 160°C. The ENR content was varied from 1 to 7 phr. The curing characteristics, morphology, mechanical properties, and automotive fuel swelling were investigated. The results indicated that the cure time of the blend rubbers was shorter as adding ENR. The mechanical properties of the blend rubbers were not affected by ENR content. However, automotive fuel resistance of the blend rubbers was found to increase with adding ENR in rubber blend.
基金support provided by the Natural Science Foundation of Jiangsu Province of China (BK2012063, BK20140973)the National Natural Science Foundation of China (31200446)
文摘Dehydrated castor oil was epoxidized using phosphoric acid as a catalyst and acetic acid peroxide as an oxidant to produce epoxidized castor oil(ECO). Ringopening polymerization with stannic chloride was used to produce polymerized ECO(PECO), and sodium hydroxide used to give hydrolyzed PECO(HPECO). The HPECO was characterized by Fourier transform infrared,1H and13 Cnuclear magnetic resonance spectroscopies,gel permeation chromatography, and differential scanning calorimetry. The weight-average molecular weight of soluble PECO and HPECO were 5026 and2274 g$mol^(–1), respectively. PECO and HPECO exhibited glass transition. Through neutralizing the carboxylic acid of HPECO with different counterions, castor oil-based polymeric surfactants(HPECO-M, where M = Na^+, K^+or triethanolamine ion) exhibited high ef ficiency to reduce the surface tension of water. The critical micelle concentration(CMC) values of HPECO-M ranged from0.042 to 0.098 g$L^(–1)and the minimum equilibrium surface tensions at CMC(g cmc) of HPECO-M ranged from 25.6 to30.0 m N$m^(–1). The water-hexadecane interfacial energy was calculated from measured surface tension using harmonic and geometric mean methods. Measured values of water-hexadecane interfacial tension agreed well with those calculated using the harmonic and geometric mean methods.
文摘This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). SEM images showed the reduction in fiber size with ENR content of up to 25% in the mixture PLA/ENR. FTIR analysis revealed a possible interaction between carboxylic group of PLA and epoxi group of ENR. Thermal analysis showed the increase of the crystallinity fraction with ENR content and a decrease in thermal stability of eletrospun mats with the addition of ENR. The dynamic mechanical properties showed an enhancement of the stiffness of PLA/ENR blends with the increase of ENR content, which can support the production of interesting materials for tissue engineering based on renewable and biocompatible polymers. The reported properties indicate the possibility to use such fiber mats as potential materials in tissue engineering.
文摘The natural rubber (NR) was mixed with fluoro elastomer (FKM), due to the difference of polarity in NR and FKM made this blend incompatible so the third component was used. NR/FKM blended with the blend ratio of 70/30 was prepared by using a two-roll mill and vulcanization in a compression mold at 180℃ using peroxide as a curative agent. Epoxidized natural rubber (ENR) or polyisoprene-graft-maleic acid monomethyl ester (PI-ME) was used as a third component. The curing characteristics, morphology, mechanical properties, and automotive fuel swelling were investigated. The results indicated that the scorch time and cure time of the blend rubbers were longer as adding ENR or PI-ME. Both mechanical properties and automotive fuel resistance of the blend rubbers were found to increase with adding ENR in rubber blend. Conversely for adding PI-ME, automotive fuel resistance of the blend rubbers was found to decrease progressively with increasing PI-ME content.
文摘Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable sources in the manufacture of rubber products. The aim of this work is to investigate the possibilities of using elastomers and ingredients from renewable sources—epoxidized natural rubber, silica obtained by rice husks incineration and microcrystalline cellulose—as fillers and rapeseed oil as a process additive in compositions, intended for the manufacture of soles for winter footwear having an increased coefficient of friction to icy surfaces. The tribological tests based on the coefficient of friction evaluated the adhesion of the composites to the icy surfaces at different temperatures. The complex evaluation of developed composites revealed those containing microcrystalline cellulose and biogenic amorphous silica at a 1:1 ratio as the most suitable for making footwear soles because of the best combination of physicо-mechanical properties and coefficient of friction.
文摘In this work, polyester polyols with high weight average molecular weight （Mw） （Mw= 10000-15000） were prepared from epoxidized palm olein （EPOo） and a series of dicarboxylic acids （C6-C12） at elevated temperature under non-catalyzed condition. The optimal reaction conditions were determined as 180 ℃ for 4 h. Longer carbon chain length of dicarboxylic acids was more reactive when reacted with EPOo. The physical appearance of the product was observed as liquid at room temperature. This palm oil-based polyester polyol is proposed as starting material for flexible polyurethane. For reaction monitoring purposes, FTIR was used while 1H NMR analysis was carried out to characterize the important functional groups of the products. The effects of reaction time and temperature on the Mw of the reaction mixture were also studied by GPC.
基金Fundamental Research Funds of CAF(No.CAFYBB2017QA017)Natural Science Foundation of Jiangsu Province(No.BK20161122)。
文摘A novel phosphorous-containing acrylated epoxidized soybean oil-based(P-AESO)resin was developed via the ring-opening reaction of epoxidized soybean oil(ESO)with diphenylphosphinic chloride(DPPC),followed by acrylation of the resulting groups.The chemical structure was characterized by Fourier transform infrared spectroscopy(FT-IR),and ^(1)H nuclear magnetic resonance(^(1)H NMR).Subsequently,the viscosity and volumetric shrinkage of the obtained P-AESO resins were studied.Then the oligomer was formulated into UV-curable coatings,and the mechanical,thermal,and coating properties of the resulting UV-cured bioresins were studied by tensile testing,dynamic mechanical thermal analysis(DMA),thermogravimetric analysis(TGA)coupled with FT-IR spectroscopy(TGA-FT-IR),hardness,adhesion,pencil hardness and chemical resistance.Furthermore,the UV-curing behavior of the P-AESO resin was determined by real-time realtime infrared(RT-IR).Meanwhile,compared with coating from acrylated epoxidized soybean oil(AESO),the P-AESO system coatings showed better volumetric shrinkage,excellent adhesion,and enhanced thermal and glass transition temperature(Tg)while maintaining reasonably final C=C conversions and cross-link density.For instance,the obtained P-AESO/trimethylolpropanetriacrylate(TMPTA)20 material possessed a volumetric shrinkage of 4.1%,Tg of 115.6℃,char yield of 9.47%,and final C=C conversions of 81.4%respectively,which exhibited superior values than that of the AESO/TMPTA20 material.The improvement of the P-AESO coating performances could contribute to the architectures that combined the structural features of phosphorous-containing rigid benzene.The developed P-AESO resin is promising for applications in the UV-curable coatings.
基金Financial supports by the National Natural Science Foundation of China (Nos.51761135132 and 51822304) are sincerely acknowledged。
文摘A novel kind of fully bio-based PSAs we re obtained through the curing reaction between two components derived from the plant oils:carboxyl-terminated polyricinoleate(PRA) fro m the castor oil and epoxidized soybean oil(ESO).The get content,glass transition temperature(Tg),rheological behavior,tensile strength,creep resistance and 180° peel strength of the PSAs were feasibly tailored by adjusting the component ratio of ESO to PRA.At low cross-linking level,the PSAs behaved like a viscous liquid and did not possess enough cohesiveness to sustain the mechanical stress during peeling,The PSAs cross-linked at or near the optimal stoichiometric conditions displayed an adhesive(interfacial) failure between the substrate and the adhesive layer,which were associated with the lowest adhesion levels.The PSAs with the dosage amount of ESO ranging from 10.20 wt% were tacky and flexible,which exhibited 1800 peel strength ranging from 0.4~2.3 N/cm;and could be easily removed without any residues on the adherend.The process for the preparation of the fully bio-based PSAs was environmentally friendly without using any orga nic solve nt or other toxic chemical,herein showing the great potential as sustainable materials.
