D4/D4Vi阴离子开环乳液共聚动力学及乳胶粒径

采用阴离子开环乳液聚合法制备了聚硅氧烷共聚乳液,研究了反应条件对共聚动力学及乳胶粒径的影响。结果表明,初始恒速阶段的表观动力学方程为Rp=k[E]0.18[KOH]0.59[M]0.75,表观活化能为52.77 kJ/mol。乳胶粒径随反应温度升高而变小,粒径分布在80℃出现最小值。随[KOH]的增大,乳胶粒径变大,粒径分布变宽。复合乳化剂质量浓度[E]在不同范围内对乳胶粒径及其分布的影响不同,当[E]<0.0572 g/mL时,随[E]增大,乳胶粒径变小,粒径分布变窄;当[E]>0.0572 g/mL时,乳胶粒径反而变大。     

Poly(methyl methacrylate)/hyperbranched polysiloxane hybrid prepared by gamma-radiation polymerization: Thermal stability,optical transparence,and UV shielding

It is challenging to endow poly(methyl methacrylate) (PMMA) with good dielectric properties and UV absorption capacity while simultaneously overcoming its poor heat resistance. Herein, we report for the first time a novel organic–inorganic hybrid (PMMA-HBPSi) derived from methyl methacrylate (MMA) and hyperbranched polysiloxane (HBPSi) fabricated via γ-radiation curing. The typical properties (thermal stability, optical characteristics, and dielectric properties) of the hybrids were systematically investigated and discussed. The results demonstrated that the incorporation of HBPSi into the PMMA resin not only increased the thermal resistance, dimensional stability, and dielectric properties but also remarkably reduced the UV transmittance. Specifically, in comparison with pure PMMA, the initial degradation temperature (T_di) of PMMA-HBPSi increased by 31°C, with no phase transition occurred in a temperature range of 60–230°C, thus illustrating a significant improvement in the glass-transition temperature. Moreover, the thermal expansion coefficient decreased by 86.9% at temperatures exceeding 118°C. The UV transmittance of PMMA was also found to decrease by 80% at 295 nm after the introduction of HBPSi. These attractive features of PMMA-HBPSi demonstrate that the new approach proposed here is suitable for developing high-performance organic glasses for optical, aviation, and electronic applications.     

聚氧乙烯接枝聚硅氧烷的乳化性及离子导电性

研究了规整聚氧乙烯（ＰＥＯ）接枝聚硅氧烷的结构对乳化性、结晶度及其与ＬｉＣｌＯ４络合物的导电率的影响。接枝共聚物由分子量大于３０００的聚氧乙烯大单体与聚甲基氢基硅氧烷通过双键的硅氢化反应得到。结果表明，共聚物用量很小即可获得较大的乳化体积；减小枝链的分子量有利于乳化，共聚物中聚氧乙烯的结晶度随其含量的减少而降低。共聚物与锂盐的络合物的离子导电率在２５℃可达１×１０－５Ｓ／ｃｍ以上。含８５％聚氧乙烯的共聚物在ＥＯ／Ｌｉ＝２０／１的条件下导电率最大。     

Synthesis of rodlike polysiloxane containing polyol moieties derived from glucose with regularly controlled higher-ordered structure

A rodlike polysiloxane (3) containing polyol moieties derived from the sugar has been synthesized by reaction of an amine-functionalized rodlike polysiloxane (1) with gluconolactone (2) in the presence of triethylamine in DMF. Formation of 3 was estimated by the IR and ¹H NMR measurements. The functionality of 2 to the amino groups in 1 was ca. 75%, based on the ¹H NMR spectrum of the product. The XRD profile of 3 showed three peaks for a typical hexagonal phase, and the d-value of (100) peak of 3 was larger than that of 1, indicating the regularly controlled higher-ordered structure of 3.     

甲基含氢硅油的合成

本文介绍了用固体催化剂合成甲基含氢硅油的新工艺技术及其新旧方法的对比和两者的差别。     

聚硅氧烷侧链高分子液晶的合成

合成了烯丙氧基苯甲酸对甲氧基苯酚酯（ＡＢＰＭ）和烯丙基胆甾醚（ＡＣＥ），用ＮＭＲ及ＭＳ对其结构进行了鉴定。通过上述两种化合物的末端双键与含氢硅油的Ｓｉ－Ｈ进行催化加成反应，得到了含侧链的聚硅氧烷，红外光谱证明，大部分Ｓｉ－Ｈ已参加了反应。聚合物具有液晶性，聚物和共聚物的液晶相具有不同的特点，分属于向列型，近晶型和胆甾型。     

汽车用耐刮擦改性聚丙烯的研制

制备了汽车用耐刮擦改性聚丙烯(PP),分析了不同耐刮擦滑爽剂、矿物填料、PP结晶度及增容剂等对材料耐刮擦性能的影响。结果表明,采用高结晶PP、较小粒径的矿物填料和反应型高聚硅氧烷制备的改性PP具有优异的耐刮擦性能,完全适用于汽车零部件。     

低介电常数聚合物材料的研究进展

综述了低介电常数(low-k)材料研究的基本情况,以及可用于微电子领域的低介电常数聚合物材料,包括材料的化学结构和基本物理性质。并着重介绍了带有纳米孔的超低介电常数材料的研究进展。同时,对低介电常数材料的制备工艺也进行了简要的总结。     

Synthesis of a polyethylene glycolylated polysiloxane system through a two-step procedure and its compatibility

Acrylic macromonomer was synthesized by esterification of acrylic acid (AA) and PEGylated siloxane alcohol. And the acrylic macromonomer was employed as unsaturated precursor for the hydrosilylation with polymethylhydrosiloxane (PMHS). FTIR, ¹H, ¹³C, ²⁹Si-NMR, and TGA proved that PEGylated polysiloxane was successfully synthesized. The morphological studies revealed that the dimples in the cross sections were attributed to polyethylene glycol (PEG) phase domains with diameters of 5–15 μm. The contribution of polar and dispersion factor toward surface energy was studied by contact angle (CA) measurement. The results showed that wetting behavior could transform from hydrophobic to hydrophilic with the CA from 122° to 54°. The final PEGylated polysiloxane provided sufficient compatibility and good wetting behavior, in contrast with silane ethers or alkyl silanes, indicating that it might be utilized as an alternate candidate for personal care. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47889.     

Epoxy-functionalized polysiloxane reinforced epoxy resin for cryogenic application

The poor cryogenic mechanical properties of epoxy resins restrict their extensive application in cryogenic engineering fields. In this study, a newly synthesized epoxy-functionalized polysiloxane (PSE) is used to improve the cryogenic mechanical properties of bisphenol-F epoxy resin. The Fourier transform infrared spectra and nuclear magnetic resonance confirm the formation of epoxy-functionalized –Si–O–Si– molecular chain. The surface free energy test results show that the PSE has a better compatibility with epoxy resin. The mechanical test results show that the cryogenic tensile strength, failure strain, fracture toughness, and impact strength of epoxy resin is improved significantly by adding the suitable amounts of PSE. Compared to the neat epoxy resin, the maximum tensile strength (196.92 MPa, an improvement of 11.2%), failure strain (2.97%, an improvement of 33.8%), fracture toughness (3.05 MPa·m^1/2, an improvement of 30.7%) and impact strength (40.55 kJ m⁻², an improvement of 14.8%) at cryogenic temperature (90 K) is obtained by incorporating 10 wt % PSE into the neat epoxy resin. Moreover, the results also indicated that the tensile strength, Young's modulus, and fracture toughness of epoxy resin with the same PSE content at 90 K are higher than that at room temperature (RT). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46930.