Liquid-nitrogen quenching was applied to study the enthalpy effect on the stress-induced crystallization of microbial polyesters. Crystallization bands of poly(3-hydroxybutyrate) exhibited the potential to reveal the stress distribution in the melt; while crystallization of poly[(3-hydroxybutyrate)-co-(3-hydroxyhexanoate)] gave shishkebab structures. Polarized-light micrographs confirmed that the enhanced nucleation was attributed to the tensile stress. Furthermore, control of the quenching direction provides a method to direct the lamellar growth. Polarized-light micrographs ofPHBfilm crystallized at 90 8C after quenching in liquid nitrogen from the melt. The normal of the bands, namely the lamellar growth direction, runs predominantly parallel to the stress direction.

Melting and crystallization of two types of polyhydroxyalkanoates (PHAs), poly (3-hydroxybutyrate) homopolymer (PHB) and poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) random copolymer (PHBHHx) were studied via in situ Fourier transform infrared spectroscopy (FTIR). The absorbance variances of the crystalline and the amorphous bands revealed that melting of PHB occurred at a narrow temperature range, while melting of PHBHHx copolymer occurred at a wide temperature range, and it was shown that the latter had a much wider distribution of lamellar thickness. These results were consistent with those from DSC. The alkyl groups reached close packing prior to crystallization in PHB and followed the crystallization in PHBHHx due to the longer branch propyl group. The band at 1230 cm21 was first assigned to the conformational band of the helical segments, and the absorbance ratio of the band at 1230 cm21 to the reference band at 1453 cm21 was used to quantitatively determine the crystallinity of PHAs after adjustment with DSC. Since further crystallization usually occurs in PHAs during heating and DSC could not reveal the original crystallinity in these samples, we suggest FTIR as an effective and nondestructive tool to evaluate crystallinity of PHAs.

增加聚丙烯（PP）极性的方法很多，最常用的是熔体接枝法，但是它的最大缺点是无法得到高接枝率的极性PP。该文研究了马来酸酐（MAH）固相接枝PP的方法，通过对反应方法的优化得到了接枝率较高的MAH接枝PP。与通常采用的熔体接枝法进行对比，固相接枝法是一种有效的得到高接枝率MAH功能化PP的方法。分析了MAH固相接枝PP产品中酸酐含量，将滴定法和红外分光光度法结合，通过线性拟合得到了定量分析测定酸酐含量的工作曲线与公式，可用于快捷表征酸酐功能化聚丙烯中的酸酐含量。

Functional monomers, maleic anhydride (MAH) and vinyl acetate (VAc), were used as comonomers in the solid-phase grafting of polypropylene (PP). Quantitative determination of the graft level of both MAH and VAc performed by titration and FTIR methods allowed for a good appreciation of the interaction of MAH and VAc. A product with high-graft level of both VAc and MAH was obtained when the feeding molar ratio of MAH/VAc approached 1:1. The melt flow rate (MFR) of the grafted PP decreased with the increase in the feeding amount of VAc. It was proposed that MAH and VAc molecules could form a kind of stable transition state during the graft polymerization and that the reactivity of both monomers were enhanced. The resulting multifunctional PP offers possibility for the development of novel PP-based polymer blends and composites, thus extending the application field of PP.

为改善尼龙6（PA6）的力学性能，加入碳nm管（CNTs与之复合，制作CNTs/PA6复合材料，以提高基体PA6的力学性能，特别是抗拉强度。通过采用原位法复合CNTs与PA6，获得了由C-O-C化学键连接的、理想的CNTs/PA6界面的、且CNTs在基体PA6中分散均匀的CNTs/PA6 复合材料，其抗拉强度有较大幅度的提高，同时还保持较高的冲击韧性和延伸率。经检测，CNTs/PA6复合材料的断裂界面不象其它纤维增强PA6复合材料那样在纤维/PA6界面上，而是在PA6包裹层与PA6基体界面上。研究结果表明，采用原位复合法，CNTs能够对PA6基体起到很好的增强作用。