摘要
以端羟丙基聚二甲基硅氧烷(HP-PDMS)、异佛尔酮二异氰酸酯、2,2-二羟甲基丁酸等为主要原料,采用分步投料法和无皂相反转乳化工艺制得粒径约50 nm的有机硅-聚氨酯共聚乳液,并对有机硅-聚氨酯乳胶膜的相结构和性能进行了表征,考察了HP-PDMS用量对乳胶膜相结构和性能的影响.DSC测试结果显示,与聚醚型聚氨酯乳胶膜相比,有机硅-聚氨酯乳胶膜中存在明显的相分离结构.FTIR分析结果表明,有机硅-聚氨酯乳胶膜硬段之间存在较强的氢键,它促进了相分离结构的形成.从AFM相图上可以观察到有机硅-聚氨酯乳胶膜中存在明显的海岛型相分离结构,其中聚硅氧烷软段的无定形微区构成了岛状分散相.随着有机硅含量的增加,有机硅-聚氨酯乳胶膜的相分离程度增加,弹性模量降低,断裂伸长率和柔韧性显著升高.有机硅-聚氨酯乳胶膜的起始分解温度低于聚醚型聚氨酯乳胶膜,但其在高温阶段的稳定性明显优于后者;对乳胶膜接触角和吸水率的研究表明,有机硅-聚氨酯乳胶膜的耐水性远高于聚醚型聚氨酯乳胶膜.
Using hydroxypropyl terminated polydimethylsiloxane（HP-PDMS）,isophorone diisocyanate and2,2-bis（hydroxymethyl） butyric acid as starting materials,silicone-polyurethane copolymer（Si-PU） latexes with particle diameter of about 50 nm were prepared via step-by-step feeding process followed by phase inversion technique in the absence of surfactant. Influences of the HP-PDMS content on the phase structure and the properties of the Si-PU latex films were investigated,and the difference between Si-PU and polyether polyurethane（E-PU） was emphasized. It was found that the content of PDMS in Si-PU could reach up to65 wt%. Results of DSC analysis showed that,in comparison with the E-PU latex film,the Si-PU latex films exhibited well phase separation. Strong hydrogen bonding in Si-PU hard segments was confirmed by FTIR,which promoted the micro-phase separation in the latex films. On the contrary,strong hydrogen bonding existed in between the soft and hard segments in E-PU,which led to phase mixing and prevented the formation of phase separation structure. The Si-PU latex films were characterized by AFM tapping mode and the formation of sea-island phase separation was observed,and this kind of phase separation structure in the Si-PU latex films was rarely reported in the literature,in which the amorphous PDMS-enriched domains constituted the dispersed phases. With the increase in HP-PDMS content,the degree of phase separation in the Si-PU latex films increased as well,which led to the decrease of elastic modulus from 400. 0 MPa to 32. 2 MPa with an increase in elongation at break and in the flexibility. The initial decomposition temperature of the Si-PU latex films was at about 244 ℃,which was 18 ℃ lower than that of the E-PU latex film due to the low degree of hydrogen bonding between the soft and the hard segments,whereas the thermal stability of Si-PU at high temperature zone was much better than E-PU. Compare to the E-PU latex film,a low water adsorption rate under 11% and a high contact angle above 94�
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2016年第12期1686-1694,共9页
Acta Polymerica Sinica
基金
国家重点基础研究发展计划(973计划
项目号2014CB932202)资助项目
关键词
聚氨酯
有机硅
相分离
结构-性能关系
Polyurethane
Silicone
Phase separation
Structure-property relationship
