共查询到17条相似文献,搜索用时 146 毫秒
1.
2.
3.
用DSC分别探讨了苯酰化聚苯醚(PPO)(BA~(31.0)-PPO和BA~(43.4)-PPO)/PPO共混体系的热焓松弛变化规律与差异.发现已知是相容体系的BA~(31.0)-PPO/PPO在低于T_g等温退火过程中只出现一个吸热峰;典型的相容体系PPO/PS也表现出类似的行为.而未知相容性的BA~(43.4)-PPO/PPO在等温退火过程中出现两个吸热峰,此两峰的T_p值随退火时间的变化类似于各纯组分相应条件下的变化.电子显微镜结果表明,BA~(43.4)-PPO/PPO是相分离体系.因此对T_g非常接近的较刚性主链的PP0及其改性物的共混体系可用热焓松弛行为确定其相容性. 相似文献
4.
研究了聚苯醚PPO、羧化PPO、苯酰化PPO、苯磺酰化PPO和磺化PPO在不同溶剂中的溶解能力,分别讨论了各种取代基以及取代度对聚合物溶解性能的影响,由PPO衍生物的特性粘数估算了它们的溶度参数。 相似文献
5.
6.
7.
8.
9.
研究了同时具有最高临界互溶温度和最低临界互溶温度的羧化聚苯醚/聚苯乙烯共混体系随退火温度的变化而发生的相形态结构的变化.研究了此共混体系的相分离机理.并发现了此特殊共混体系低温和高温区的相分离机理是不同的.从分子的结构和分子间特殊相互作用上探讨了此共混体系产生特殊相行为的原因. 相似文献
10.
本文从溶液行为和固体热行为对聚(2,6-二甲基1,4-苯醚)(PPO)离聚体(磺化聚苯醚或接化聚苯醚)/聚(苯乙烯-4-乙烯吡啶)(PS-VP)共混物进行了研究。DSC研究表明磺化度为7.7%mol的SPPO/PS-VP和羧化度为15%molCPPO炉S-VP在整个组成范围都是相容的。溶液行为研究表明,与对应的PPO/PS-VP共混物相比,这两个系列的共混物都表现出较高的比浓粘度。这是由于聚苯醚离聚体上的酸基发生质子转移,两组分间强烈的离子-离子相互作用导致分子间的络合,从而使比浓粘度的提高,也正是这种离子-离子相互作用使得这两对共混物完全相容。 相似文献
11.
PPO/SEBS-g-MAH共混体系的形态结构与冲击性能 总被引:8,自引:0,他引:8
从亚微相态和冲击性能出发 ,对比了采用熔融挤出法制备的PPO/SEBS和PPO/SEBS g MAH两种共混物 .结果表明 ,在本文所研究的弹性体用量范围内 ,PPO/SEBS为“海 岛”型结构 ,而PPO/SEBS g MAH呈现网状结构 ;PPO/SEBS体系无脆韧转变现象 ,PPO/SEBS g MAH体系则在弹性体用量为 10 %~ 15 %时出现明显的脆韧转变 ,缺口冲击强度达到 95 0J/m ,这种超韧现象源于其网状结构的形成 .文中进一步用DSC和毛细管流变仪对共混体系的热性能和流变性能进行了测试 ,探讨了PPO/SEBS g MAH共混物网状结构的形成原因 相似文献
12.
S. Li L. Charles Dickinson James C. W. Chien 《Journal of Polymer Science.Polymer Physics》1994,32(4):607-613
Solid-state NMR relaxation has been used to explore the distribution of components in poly(phenylene oxide) (PPO) high impact polystyrene (HIPS) and PPO/poly(styrene-b-butadiene-b-styrene) (SBS) blends. The nuclear relaxation of PPO in the former system is single exponential for all compositions, but the relaxation of PS in the blend is simple exponential only when the PPO content is low but is otherwise nonexponential. The nuclear magnetization decay curves were analyzed in terms of statistical compositional fluctuation at the scale of spin diffusion distances of several nm. Distribution functions for nuclear relaxation and for blend composition have been derived. Extraction of low molecular weight occluded PS from HIPS resulted in blends having reduced homogeneity. Addition of low molecular weight PS enhanced homogeneity in both the PPO/HIPS and PPO/SBS blends. © 1994 John Wiley & Sons, Inc. 相似文献
13.
There have been a few reports that discussed polymer blends with compositional gradient in their sheet directions. Thus, we discussed the preparation of the graded polystyrene(PS)/styrene-hydorogenated butadiene- styrene block copolymer(SEBS) blend with compositional gradient in their sheet directions, by applying of the solution-diffusion method. Then, the hardness on the air side surface of the graded blend gradually increased with shifting the measured point from the edge containing lowest PS content. All of the areas, into which the graded blend sheet was divided, were almost equal in length, when total elongation was 6.6 mm. However, the length of the area became longer at the larger SEBS content, when the total elongation was 175 mm. The ratio of the length of the area to that in lowest SEBS content increased gradually with increasing of SEBS content, when the total elongation became over 50 mm. It was considered that this phenomenon occurred, because of the compositional gradient in the PS/SEBS graded blend. 相似文献
14.
Mechanical and physical properties of polypropylene (PP)/polystyrene (PS) blend, PP/PS/polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) ternary blend and their composites with carbon nanofibers (CNF) were investigated. Composites of ternary blend exhibited superior properties compared to those of binary blends. Mechanical performance of nanocomposites was intimately related to their phase morphology. PP/PS/SEBS/0.1 wt% CNF hybrid composites exhibited excellent impact strength (Four-fold increase compared to PP/PS blend) and ductility (12-fold increase in elongation at break, with respect to PP/PS blend). Moreover, these composites displayed good tensile strength and modulus (15% increase in Young's modulus, compared to PP/PS/SEBS blend) and are suitable for various end-use applications including automobile applications. Although crystallinity of PP phase is decreased by the incorporation of CNF, thermal stability of the composites remained almost unaffected. Contact angle measurements revealed that ternary composites exhibited maximum hydrophobicity. 相似文献
15.
HIPS-g-GMA相容剂对PC/HIPS共混物相容性的影响* 总被引:3,自引:0,他引:3
将两种或两种以上聚合物进行共混是获得性能优异合金材料的简单而有效的途径[1,2 ] .但是大多数聚合物共混时 ,由于混合焓ΔH >0且混合熵ΔS非常小 ,导致混合自由能大于零 ,故大多数共混体系是不相容的 .而对于不相容的共混 ,由于两相间的界面张力大 ,两相间形成锐形界面 ,两相之间的界面粘结力低 ,导致材料性能很差 .为了改善两相间的相容性 ,需要加入相容剂[3 ,4 ] .绝大多数增容剂是嵌段或接枝共聚物 .这类增容剂分子量较大 ,在加工条件下 ,由于其粘度较大往往难于迁移到两相的界面处 ,起不到应有的增容作用 .聚合物反应加工技术是近 2… 相似文献
16.
17.
聚苯醚/聚苯乙烯共混物溶液浇铸膜的热演化行为 总被引:1,自引:0,他引:1
聚苯醚与聚苯乙烯共混物是目前相容性最好的共混体系之一。几十年来人们对该共混体系相容的原因进行了广泛的研究^[1-4]。聚苯醚是半结晶聚合物,在溶剂或溶剂蒸气存在的条件下容易形成结晶,溶剂的性质及结晶的条件都会影响聚苯醚的结晶结构及其形态^[5-8]。用溶液共昆、凝聚成膜的方法制备共混物时,一种结晶性高分子怎样与另一种高分子演化成相容的非晶共混体系,是一个比较有意义的研究课题。本文运用DSC方法,研究了聚苯醚与聚苯乙烯两者溶液共混凝聚成膜后,在各种热历史条件下结晶结构的消亡和演化成非晶相容体系的行为。 相似文献