核－壳型弹性体对热塑性树脂的增韧

本文阐述了橡胶微粒对热塑性树脂的增韧机理，以及核－壳弹性体对塑料共混物性能的影响。其目的是为合成抗冲改性用核－壳弹性体提供参考。     

生物基氢化香豆素增韧环氧树脂的制备及性能

通过生物基原料氢化香豆素(DHC), 在铬(Ⅲ)络合物和氯化铵复合物协同催化作用下, 与环氧醚类物质交替共聚, 获得一类三维网状聚合物, 进而与环氧树脂(EP)单体在固化过程中构建双网络结构, 实现有效的应力传递和外部能量吸收, 达到对环氧树脂增韧增强的效果. 凝胶渗透色谱结果表明, DHC基网络(DHC-net)分子量随反应时间延长而增加. ¹H NMR证实了合成的DHC-net分子结构. 同时, 考察了环氧树脂的热力学及力学性能, 发现DHC-net与环氧树脂基体具有良好的相容性; 改性后的环氧树脂断裂伸长率比纯环氧树脂有大幅提高; 拉伸与冲击测试显示, DHC-net含量小于30%时, 改性后环氧树脂的拉伸强度和抗冲击强度均比纯环氧树脂有大幅提高.     

Miscibility,intramolecular specific interactions and mechanical properties of a DGEBA based epoxy resin toughened with a sliding graft copolymer

The "sliding graft copolymer'(SGC), in which many linear poly-ε-caprolactone(PCL) side chains are bound to cyclodextrin rings of a polyrotaxane(PR), was prepared and employed to toughen diglycidyl ether of bisphenol A(DGEBA) based epoxy resin. The aim of the work is to understand the effect of SGC on the miscibility, morphology, thermal behavior, curing reaction and mechanical performance of the cured systems. From differential scanning calorimetry(DSC) analysis and dynamic mechanical thermal analysis(DMTA) of DGEBA/SGC thermosetting blends, it is found that DGEBA and SGC are miscible in the amorphous state. Fourier transform infrared spectroscopy(FTIR) suggested that the miscibility between SGC and DGEBA is due to the existence of intermolecular specific interactions(viz. hydrogen bonding). The impact strength is improved by 4 times for DGEBA/SGC(80/20) blends compared with that of the unmodified system. The increase in toughness of SGC-modified thermosets can be explained by the effect of intermolecular specific interactions of SGC with DGEBA, which is beneficial to induce the plastic deformation of matrix. This is the first report on utilizing this novel supramolecular polymer to toughen rigid epoxy matrix.     

聚六亚甲基碳酸酯二醇增韧环氧树脂的固化动力学

The kinetics of the cure reaction for the system consisting of bisphenol-A diglycidyl ether, No.70 anhydride, Polyhexamethylene Carbonate Diol(PHMCD) and DMP-30 has been studied. By use of differential scanning calorimetry(DSC) under isothermal condition, the reaction is found to proceed first via autocatalytic mechanism up to a conversion of 0.3 and then become a first order reaction over a temperature range of 130~160 ℃. The kinetic parameters of the curing reaction have also been determined with both E1 = 63.74 kJ.mol-1, lnA1=13, lnA2 = -3for the autocatalytic mechanism and E =64.68 kJ•mol-1, lnA = 13.8 for the first order mechanism.