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小角X射线散射技术在高分子表征中的应用 被引量:8
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作者 吕冬 卢影 门永锋 《高分子学报》 SCIE CAS CSCD 北大核心 2021年第7期822-839,I0006,共19页
小角X射线散射(SAXS)技术是表征高分子材料微观结构的一种重要手段.当X射线穿过材料时,在材料不均一的电子云密度分布作用下,发生散射并形成特定的散射图案,使得我们可以根据特定的模型来反推材料的微观结构,并计算相关结构参数.SAXS特... 小角X射线散射(SAXS)技术是表征高分子材料微观结构的一种重要手段.当X射线穿过材料时,在材料不均一的电子云密度分布作用下,发生散射并形成特定的散射图案,使得我们可以根据特定的模型来反推材料的微观结构,并计算相关结构参数.SAXS特有的对微观结构的统计平均及无损探测使其成为了一种不可或缺的高分子材料微观结构分析手段.本文首先简述了SAXS技术的基本理论,在此基础上根据测试中的实际问题给出了测试时可采取的实验技巧.最后,结合典型实例,概述了高分子材料中可用SAXS技术表征的微观结构及其相应的理论模型.希望本文能作为入门文献,帮助初学者更好地理解SAXS技术的原理,并结合实际需求迅速了解SAXS技术的适用范围及相关实验技巧,高效地完成相关实验. 展开更多
关键词 高分子表征 小角X射线散射(SAXS) 片晶 微观结构
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Simultaneous enhancements of strength and toughness by multiscale lamellar structure in Ti_(2)AlNb based intermetallic
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作者 Fan Zhang Weidong Zeng +2 位作者 Penghui Zhang Haoyuan Ma Jianwei Xu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第7期249-261,共13页
Multi-scale lamellar structure significantly improves toughness of Ti_(2)AlNb based alloys,which are inher-ently brittle intermetallics,without compromising their strength.This structure was achieved through-B2-transu... Multi-scale lamellar structure significantly improves toughness of Ti_(2)AlNb based alloys,which are inher-ently brittle intermetallics,without compromising their strength.This structure was achieved through-B2-transus-forging(TBTF)combined with O+B2 two-phase region heat treatments.Various types of multi-scale lamellar structures were obtained by controlling the cooling rate after TBTF.These variations were mainly attributed to differences in the distribution,content,and size of the thick lamellar O phase and the size and crystallographic orientation of B2 grain.By analyzing the microstructural characteristics and crystallographic orientation near the crack propagation path,it was found that the crack propaga-tion resistance of thick lamellae,sub grain and grain boundaries(GBs)O phase increased sequentially,accompanied by more tortuous crack propagation path.Moreover,B2 grains with high misorientation significantly deflected the crack propagation by cleavage ridges between adjoining cleavage planes.Addi-tionally,the development of numerous secondary cleavage ridges,resulting from the transition through varying secondary cleavage planes in distinct sub B2 grains,further hindered the quick propagation of cracks.It was clarified that the cleavage planes were dominantly belonging to{110}.These findings pro-vided valuable guidance for the design of damage tolerance strategies for Ti_(2)AlNb-based intermetallics. 展开更多
关键词 Multiscale lamellae structure Fracture toughness Crack propagation Ti_(2)AlNb-based intermetallic Through-B2-transus-forging
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TRANSMISSION ELECTRON MICROSCOPY OF SEGMENTED POLYURETHANES WITH RUTHENIUM TETROXIDE AS A STAINING AGENT
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作者 肖凤飞 陈寿羲 +2 位作者 金永泽 施良和 徐懋 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1991年第3期246-250,共5页
Microphase separation and lamellar structure of segmented polyether- and polyester-polyurethanes have been investigated by means of transmission electron microscopy with the ruthenium tetroxide staining technique. The... Microphase separation and lamellar structure of segmented polyether- and polyester-polyurethanes have been investigated by means of transmission electron microscopy with the ruthenium tetroxide staining technique. The results show that the RuO_4 staining technique is simpler and may give better image contrast than other staining methods for this polymer. Microphase separation and lamellar structure of segmented polyether-and polyester-polyurethanes were directly observed and discussed. 展开更多
关键词 Microdomain structure lamellae Ruthenium tetroxide stain Segmented polyurethane.
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Analysis of Structure Transition and Compatibility of PTT/PC Blend without Transesterification
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作者 Qing-long Song 温慧颖 +3 位作者 Jesper de Claville Christiansen Dong-hong Yu Chun-sheng Chen 蒋世春 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2016年第9期1172-1182,共11页
Poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends were prepared by solvent mixing to avoid transesterification during high temperature blending. The influences of compositions on the thermal behavior,... Poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends were prepared by solvent mixing to avoid transesterification during high temperature blending. The influences of compositions on the thermal behavior, crystallization morphology and structure of the blends were studied. FTIR results indicated that there was no CO0 linking to two phenyl groups on each side chain and DSC results supported no transesterification reaction. DSC curves showed that Tc and Tmc increased to maximum range when PC contents were between 7 wt%-15 wt%, however, Tm decreased constantly with the increase of PC contents. It was observed from POM that PTT spherulitic morphology and crystallization kinetics were obviously influenced by the change of PC contents. Structural evolutions during cooling were investigated by SAXS which showed Lc of PTT remained a constant with different PC contents and also fixed during crystallization, nevertheless, it revealed a maximum value of Lnc for sample PTT93. It was concluded that PC chains could be permeated into not only amorphous crystallite structure but also amorphous lamellae structure and 7 wt% PC content was supposed to be the "proper" penetration amount into PTT lamellae structure which led to a maximum capacity of amorphous lamellar layer. Fringedmicelle crystal model was adopted to illustrate semi-crystalline physical structures of the blend in two kinds of component aggregation states. 展开更多
关键词 Solvent mixing TRANSESTERIFICATION lamellae structure Fringed-micelle.
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Folded-chain lamellae interphase in flexible polymers
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作者 朱清仁 庞文民 +1 位作者 张裕恒 黄元华 《Chinese Science Bulletin》 SCIE EI CAS 1996年第16期1347-1352,共6页
In a semicrystalline aggregate of flexible chain polymers, a large amount of the adjacent regularly-folded tiny lamellae coexists with the amorphous phase whose chains have only random spatial arrangement. This ’crys... In a semicrystalline aggregate of flexible chain polymers, a large amount of the adjacent regularly-folded tiny lamellae coexists with the amorphous phase whose chains have only random spatial arrangement. This ’crystalline-noncrystalline’ two-phase model has been widely accepted and used to describe the structure and properties of polymers in condensed state. The crystalline morphology of PE prepared by various methods have 展开更多
关键词 CRYSTALLINE PE phase structure INTERPHASE 13C NMR folded-chain lamellae
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硬弹性聚丙烯的排状堆积片晶 被引量:1
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作者 胡继文 沈家瑞 黄勇 《应用化学》 CAS CSCD 北大核心 2003年第5期466-469,共4页
用广角X射线衍射、小角X光散射等手段对硬弹性聚丙烯中排状堆积片晶的形成及结构进行了研究。结果表明 ,应力场下聚丙烯熔体结晶 ,得到的硬弹性聚丙烯具有垂直于挤出方向而又平行堆积的片晶结构 (即排状堆积片晶 )。熔融温度越高 ,排状... 用广角X射线衍射、小角X光散射等手段对硬弹性聚丙烯中排状堆积片晶的形成及结构进行了研究。结果表明 ,应力场下聚丙烯熔体结晶 ,得到的硬弹性聚丙烯具有垂直于挤出方向而又平行堆积的片晶结构 (即排状堆积片晶 )。熔融温度越高 ,排状堆积片晶所需的熔体拉伸比越高。而随着熔体所受拉伸比的增加 ,片晶厚度有所增加。随着熔融温度升高 ,片晶厚度下降。热处理温度在 1 1 0~ 1 2 0℃之间 ,片晶厚度随热处理温度升高明显增加。 展开更多
关键词 硬弹性 聚丙烯 堆积片晶 结晶结构
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日本彩虹石榴石的矿物学特征研究 被引量:1
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作者 雷佳莉 白峰 凌潇潇 《岩石矿物学杂志》 CAS CSCD 北大核心 2019年第5期733-742,共10页
利用带能谱仪的扫描电镜、电子探针、傅立叶红外光谱仪和激光拉曼光谱仪对日本奈良县吉野郡天川村彩虹石榴石样品进行了矿物结构、化学组成及光谱学特征的研究,分析彩虹效应成因,推测其形成环境。背散射图像可见深浅不一的条带交互排列... 利用带能谱仪的扫描电镜、电子探针、傅立叶红外光谱仪和激光拉曼光谱仪对日本奈良县吉野郡天川村彩虹石榴石样品进行了矿物结构、化学组成及光谱学特征的研究,分析彩虹效应成因,推测其形成环境。背散射图像可见深浅不一的条带交互排列,能谱半定量分析显示,浅灰色条带元素组成与较纯的钙铁榴石一致,深灰色条带元素组成为含Al的钙铁榴石,两者互层形成薄层结构,这种特殊结构使光发生干涉和衍射作用从而产生彩虹效应。电子探针测试确定日本彩虹石榴石主体成分接近纯钙铁榴石。在彩虹色矿物表面(简称彩虹面),垂直的薄层结构构成衍射光栅,使入射光产生光栅衍射,而平行彩虹面生长的薄层使入射光发生干涉作用,两种作用产生的光波结合形成彩虹色。日本彩虹石榴石的反射红外光谱中可见[SiO4]峰位以及受少量Al-O结构影响的Fe-O结构峰位,其红外光谱特征与含有少量Al的钙铁榴石结构对应。激光拉曼光谱测试发现Al含量高的部分较Al含量低(或无)的部分峰位向高频方向移动2cm^-1,整体谱学特征与钙铁榴石特征一致。日本彩虹石榴石具有钙铁榴石和铝含量较高的钙铁榴石交互排列的结构,据此推测其在富Fe贫Al的环境中形成。 展开更多
关键词 彩虹效应 钙铁榴石 薄层结构 干涉 衍射
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超高分子量聚乙烯凝胶结晶膜的结晶形态X射线衍射研究 被引量:4
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作者 周贵恩 朱清仁 +3 位作者 高建峰 戚嵘嵘 洪昆仑 叶朝辉 《中国科学技术大学学报》 CAS CSCD 北大核心 1992年第4期425-431,共7页
对由准稀溶液速冷凝胶化结晶方法制备的超高分子量聚乙烯(UHMWPE)膜,应用广角及小角X射线衍射进行了研究,证明所形成的膜是片晶-分子链折叠的层积状结构。片晶折叠链的分子链方向(即C轴方向)垂直于膜面,在片晶间无规排列的分子链平行膜... 对由准稀溶液速冷凝胶化结晶方法制备的超高分子量聚乙烯(UHMWPE)膜,应用广角及小角X射线衍射进行了研究,证明所形成的膜是片晶-分子链折叠的层积状结构。片晶折叠链的分子链方向(即C轴方向)垂直于膜面,在片晶间无规排列的分子链平行膜面,具有较强的“排列”取向,片晶-无规排列链形成的大点阵间距为109(?),片晶间的无规排列链沿垂直分子链方向的统计平均间距约为4.6(?),分子链数约为4~5。这一结果在超拉伸过程中,有利于从片晶-折叠分子链到完全伸直链的转变,从而可获得超高拉伸比(λ>200)。 展开更多
关键词 超高分子量 聚乙烯 凝胶 X射线衍射
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哈弗式骨单元的微观结构模型 被引量:1
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作者 刚芹果 华筑信 孙家驹 《医用生物力学》 EI CAS CSCD 1999年第4期212-216,共5页
本文根据骨的微观结构;运用复合材料力学中的方法,构造了骨板的本构关系。建立了骨单元的微观结构模型,并给出该模型轴对称应变问题的解析解。根据该模型可知,密质骨的宏观弹性系数不仅与骨的孔隙率有关,而且还与骨组织中胶原和矿... 本文根据骨的微观结构;运用复合材料力学中的方法,构造了骨板的本构关系。建立了骨单元的微观结构模型,并给出该模型轴对称应变问题的解析解。根据该模型可知,密质骨的宏观弹性系数不仅与骨的孔隙率有关,而且还与骨组织中胶原和矿物质的含量以及胶原纤维的排列方向有关。 展开更多
关键词 骨单元 骨板 微观结核 密质骨 哈弗式
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模具流道环流协同LDPE/HDPE吹塑薄膜结构性能研究
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作者 常晓丹 张缓缓 瞿金平 《塑料工业》 CAS CSCD 北大核心 2020年第3期156-162,共7页
通过新型的旋转芯棒薄膜吹塑设备制备了低密度聚乙烯(LDPE)/高密度聚乙烯(HDPE)复合薄膜,并研究了该设备模具流道环流协同作用对吹塑聚乙烯薄膜结构和性能的影响。结果表明,制备的聚乙烯薄膜呈现一种互锁片晶结构;芯棒转速的提高对聚乙... 通过新型的旋转芯棒薄膜吹塑设备制备了低密度聚乙烯(LDPE)/高密度聚乙烯(HDPE)复合薄膜,并研究了该设备模具流道环流协同作用对吹塑聚乙烯薄膜结构和性能的影响。结果表明,制备的聚乙烯薄膜呈现一种互锁片晶结构;芯棒转速的提高对聚乙烯薄膜样品的结晶度、片晶厚度也有一定增益作用,使得结晶更完善;聚乙烯薄膜的拉伸性能和撕裂性能随芯棒转速提高都有所提升,尤其是横向力学性能,横向拉伸性能最大提升幅度为25.75%,横向撕裂性能最大提升幅度为27.64%;同时,该技术实现了在不影响聚乙烯薄膜的纵向热收缩率的情况下,大幅提高其横向热收缩率,提升幅度可达128.41%。 展开更多
关键词 旋转芯棒 聚乙烯薄膜 互锁片晶结构 力学性能 热收缩性
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