PA6/UHMWPE/HDPE-g-MAH共混物反应增容作用的研究

通过 DSC、SEM、Molau试验和力学性能测试 ,研究了 PA6/ UHMWPE共混过程中 HDPE- g- MAH对体系的增容作用、力学性能及结晶行为的影响。结果表明 ,共混体系为热力学不相容体系 ;在熔融共混过程中 ,PA6和 HDPE- g- MAH发生化学反应 ,生成的接枝共聚物对 PA6/ UHMWPE体系有增容作用 ,分散性和界面形态以及力学性能明显改善 ;共混体系中两相的结晶行为亦发生变化 ,尼龙组分的熔融热焓明显下降

官能化聚烯烃弹性体增韧PA1010体系Ⅱ.结晶行为的研究

用 WAXD、偏光显微镜 (PM)及 DSC研究了聚烯烃弹性体乙烯 - α-烯烃共聚物 (EOCP)对 PA10 10结晶行为的影响。WAXD结果显示纯弹性体 (EOCP)和接枝弹性体 (EOCP- g- MA)对 PA10 10的晶型均不产生影响。PM观察则表明共混体系中 EOCP与 PA10 10的相互作用很弱 ,在 PA10 10结晶过程中 ,大部分 EOCP被排除在球晶之外 ;而接枝 EOCP与 PA10 10存在较强的相互作用 ,大量的 EOCP- g- MA作为成核剂 ,使 PA10 10球晶向细晶化方向发展 ,而且随弹性体含量的增多而加强。DSC分析证实了接枝EOCP以异相成核剂的方式促进了 PA10 10的结晶 ,尤其是促进了 PA10 10的高温结晶

反应挤出条件对PP-g-GMA接枝率、接枝效率和熔体流动速率的影响

用反应挤出法在聚丙烯 (PP)分子链上接枝甲基丙烯酸环氧丙酯 (GMA) ,制备功能化聚丙烯 .重点讨论了单体浓度、引发剂浓度、反应温度及物料在螺杆中的停留时间等对接枝产物 PP-g-GMA的接枝率、接枝效率和熔体流动速率的影响 .结果表明 ,PP-g-GMA接枝率与加入的单体浓度成正比 ,与引发剂浓度无关 ,反应挤出的适宜温度窗口在 1 95～ 2 3 0℃之间 ,停留时间超过 1 min后接枝率与停留时间无关 ;PP-g-GMA的熔体流动速率与单体浓度成反比 ,与引发剂的用量成正比 ,在反应温度窗口内与反应挤出温度和物料停留时间关系不大 ;单体和引发剂的浓度、反应挤出温度及物料停留时间对 PP-g-GMA的接枝效率无显著影响 .

LLDPE/LLDPE-g-AA共混物的接触角及红外光谱表征

利用熔融共混的方法制备了线性低密度聚乙烯/线性低密度聚乙烯接枝丙烯酸(LLDPE/LLDPE-g-AA)共混物。用傅里叶红外光谱(FT-IR)和测定接触角的方法对不同LLDPE-g-AA含量的LLDPE/LLDPE-g-AA共混物膜的表面进行了表征。结果表明,随着共混物中LLDPE-g- AA含量的增加,水和甘油等极性液体与共混物表面的接触角下降。依据共混物的FT-IR计算了其羧基峰强度。发现极性液体与LLDPE/LLDPE-g- AA共混物膜表面的接触角越小,羧基峰强度越大。

PA46/PP-g-GMA合金的研制和表征

用反应挤出方法制备了PA46/PP-g-GMA合金。研究了合金的力学性能,吸水性与形态结构的关系。与PA46/PP相比,PA46/PP-g- GMA的力学性能如拉伸强度,杨氏模量,弯曲强度,弯曲模量以及冲击强度都有不同程度的提高。PA46/PP-g-GMA的吸水率比PS46/PP大幅度降低。用扫描电镜(SEM)研究了PA46/PP-g-GMA和PA46/PP样品的冲击断面。PA46/PP-g-GMA中的PP-g-GMA分散相粒子半径远比PA46/PP中的PP相粒子半径小和均匀。这表明改性后的PP-g-GMA与PA46的相容性有很大的改观。DMA研究结果表明,PA46 /PP-g-GMA样品的储能模量比相同组分的PP/PA46高。在组成为50/50时PA46/PP-g-GMA的软化点温度比PA46/PP高 120℃。

Blends of polyamide 1010 with ungrafted and maleic anhydride grafted high impact polystyrene

The crystallization, dynamic mechanical properties, tensile properties and morphology features of polyamidel 1010(PA1010) blends with the high impact polystyrere (HIPS) and maleic anhydride (MA) grafted HIPS(HIPS-g-MA) were examined at a wide composition range. By comparison the PA1010/HIPS-g-MA and PA1010/HIPS binary blends, it was found that the size of the domains of HIPS-g-MA was much smaller than that of HIPS at the same compositions. It was found that the mechanical properties of PA1010/HIPS-g-MA blends were obviously higher than those of PA1010/HIPS blends. When the content of PA1010 is more than 50wt% in the blends, the crystallization temperatures, T-cs, of PA1010 increase with increasing the content of HIPS-g-MA. On the other hand, when the content of PA1010 in the blends is less than 35wt% the fraction crystallization is observed. The same result is not obtained for the blends of PA1010/HIPS. These behaviors could be attributed to the chemical interactions between the two components and good dispersion in PA1010/HIPS-g-MA blends.

Blends of polyamide1010 with unmodified and maleic-anhydride-grafted high-impact polystyrene

The crystallization behaviors, dynamic mechanical properties, tensile, and morphology features of polyamide1010 (PA1010) blends with the high-impact polystyrene (HIPS) were examined at a wide composition range. Both unmodified and maleicanhydride-(MA)-grafted HIPS (HIPS-g-MA) were used. It was found that the domain size of HIPS-g-MA was much smaller than that of HIPS at the same compositions in the blends. The mechanical performances of PA1010-HIPS-g-MA blends were enhanced much more than that of PA1010-HIPS blends. The crystallization temperature of PA1010 shifted towards higher temperature as HIPS-g-MA increased from 20 to 50% in the blends. For the blends with a dispersed PA phase (less than or equal to 35 wt %), the T-c of PA1010 shifted towards lower temperature, from 178 to 83 degrees C. An additional transition was detected at a temperature located between the T-g's of PA1010 and PS. It was associated with the interphase relaxation peak. Its intensity increased with increasing content of PA1010, and the maximum occurred at the composition of PA1010-HIPS-g-MA 80/20. (C) 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 857-865, 1999.

Rheological, thermal, and morphological properties of ABS-PA1010 blends

Noncompatibilized and compatibilized ABS-nylon1010 blends were prepared by melt mixing. Polystyrene and glycidyl methacrylate (SG) copolymer was used as a compatibilizer to enhance the interfacial adhesion and to control the morphology. This SG copolymer contains reactive glycidyl groups that are able to react with PA1010 end groups (-NH2 or -COOH) under melt conditions to form SG-g-Nylon copolymer. Effects of the compatibilizer SG on the rheological, thermal, and morphological properties were investigated by capillary rheometer, DSC, and SEM techniques. The compatibilized ABS-PA1010 blend has higher viscosity, lower crystallinity, and smaller phase domain compared to the corresponding noncompatibilized blend. (C) 1999 John Wiley & Sons, Inc.

尼龙1010分别与未接枝和接枝马来酸酐的高抗冲聚苯乙烯的共混体系研究

研究了尼龙1010(PA1010)与高抗冲聚苯乙烯(HIPS)及马来酸酐官能化的HIPS(HIPS-g-MA)间的相互作用，利用DSC,DMA,SEM及拉伸测试等方法研究了不同组成比的共混物PA1010/HIPS与PA1010/HIPS-g-MA的结晶、玻璃化转变、形态及力学性能．结果表明HIPS与PA1010虽然结构相差甚远，但两者之间仍存在着一定的相互作用；而HIPS-s-MA可使PA1010的低温熔融峰变小，当HIPS-g-MA的含量≤50%时，随着其含量的增加，共混物中PA1010的结晶温度升高；当含量＞50%时，PA1010发生分级结晶行为，其结晶温度由原来的178℃降至83℃，同时HIPS-g-MA与PA1010间的相互作用变大，DMA谱上有明显的新的松驰峰．PA1010/HIPS-g-MA共混体系的拉伸性能要优于相同组成的PA1010/HIPS体系．以上现象主要是...

Hydrophobic pocket modification and humanized catalytic antibodies with glutathione peroxidase activity (I) - Preparation and characterization of haptenes and conjugates

The thiol group of glutathione (GSH) was protected by 2,4-dinitrochlorobenzene (DNCB), the product S-substituted dinitrophenyl GSH(GSH-S-DNP) was alcoholized to obtain haptenes 4 and 5 respectively. As haptenes, the two GSH derivatives were characterized by means of H-1 NMR, MALDI-TOF-MS and IR, followed by individually coupling with bovine serum albumin (BSA) via glutaraldehyde. BSB-Hp4 and BSA-Hp5 were purified by Sephadex G-25 gel filtration chromatography. For each conjugate, the average haptene-BSA ratio was 12 : 1. The electrophoresis analysis showed that the average molecular weight of each conjugate was 76 500. The CD spectrum indicated that the conjugates had more a-helix content than BSA did.

Compatibilization effect of graft copolymer on immiscible polymer blends: 1. LLDPE/SBS/LLDPE-g-PS systems

compatibilizing effect of graft copolymer, linear low density polyethylene-g-polystyrene (LLDPE-g-PS), on immiscible blends of LLDPE with styrene-butadiene-styrene triblock copolymer (SBS) has been investigated by means of C-13 CPMAS n.m.r. and d.s.c. techniques. The results indicate that LLDPE-g-PS is an effective compatibilizer for LLDPE/SBS blends. It was found that LLDPE-g-PS chains connect two immiscible components, LLDPE and SBS, through solubilization of chemically identical segments of LLDPE-g-PS into the amorphous region of LLDPE acid PS block domain of SBS, respectively. It was also found that LLDPE-g-PS chains connect the crystalline region of LLDPE by isomorphism, with serious effects on the supermolecular structure of LLDPE. The effect of LLDPE-g-PS on the supermolecular structure of LLDPE in the LLDPE/SBS blends obviously depends on the composition of the blends, but has little dependence on the PS grafting yields of LLDPE-g-PS. (C) 1998 Elsevier Science Ltd. All rights reserved.

Effects of the compatibilizer PP-g-GMA on morphology and mechanical properties of PP/PC blends

Effects of the compatibilizer polypropylene grafted with glycidyl methacrylate(PP-g-GMA) on the morphology, thermal, rheological and mechanical properties of polypropylene and polycarbonate blends (PP/PC) were studied. It was found that the addition of PP-g-GMA significantly changed their morphology. The mean size of domains reduced from 20 mu m to less than 5 mu m. The dispersed domain size is also strongly dependent upon the content of PP-g-GMA. The interfacial tension of PP/PC/PP-g-GMA (50/30/20) is only about one-tenth of PP/PC (70/30). The crystallization temperature of PP in PP/PC/PP-g-GMA is 5-8 degrees C higher than that of PP in PP/PC blends. Characterization studies based on mechanical properties, differential scanning calorimetry, rheology and morphological evidence obtained by using scanning electron microscopy support the hypothesis that an in-situ copolymer PP-g-PC was formed during the blending process. (C) 1997 Elsevier Science Ltd.

Effects of molecular weight and interaction parameter on the glass transition temperature of polystyrene mixtures and its blends with polystyrene/poly(2,6-dimethyl-p-phenylene oxide)

The glass transition temperature (T-g) of mixtures of polystyrene (PS) with different molecular weight and of blends of poly(2,6-dimethyl-p-phenylene oxide) (PPO) and polystyrene with different molecular weight (DMWPS) was studied by a DSC method. For the whole range of composition, the curves of T-g vs composition obtained by experiment were compared with predictions from the Fox, Gordon-Taylor, Couchman and Lu-Weiss, equations. It was found that the experimental results were not in agreement with those from the Fox, Gordon-TayIor and Couchman equations for the binary mixtures of DMWPS, where the interaction parameter chi was approximately zero. However, for the blends PPO/DMWPS (chi < 0), with an increase of molecular weight of PS, it was shown that the experimental results fitted well with those obtained from the Couchman, Gordon-Taylor and Fox equations, respectively. Furthermore, the Gordon-Taylor equation was nearly identical to the Lu-Weiss equation when \chi\ was not very large. Further, the dependence of the change of heat capacity associated with the glass transition (Delta C-p) on the molecular weight of PS was investigated and an empirical equation was presented. (C) 1997 Elsevier Science Ltd.

Morphology, mechanical properties and interfacial behaviour of PA1010/PP/PP-g-GMA ternary blends

Morphology, mechanical properties, and interfacial interaction of polyamide 1010/polypropylene (PA1010/ PP) blends compatibilized with polypropylene grafted with glycidyl methacrylate (PP-g-GMA) were studied. It was found that the size of the PP domains, tensile and impact strength of ternary blends, and adhesion fracture energy between two layers of PA1010 and PP were all significantly dependent on the PP-g-GMA contents in the PP layer. Correlations between morphology and related properties were sought. The improvements in properties have been attributed to chemical and physical interaction occurring between PA1010 and PP-g-GMA. (C) 1997 Elsevier Science Ltd.