膨润土杂化改性聚丙烯共混体系性能研究

以乙醇为分散介质,过氧化二苯甲酰为引发剂,硫代硫酸钠为催化剂,合成了与聚丙烯具有良好复配性能的膨润土杂化改性聚苯乙烯材料(PS/H)。研究了PP/PS、PP/(PS/H)共混体系的性能。结果表明:原位悬浮聚合产物粒子中存在PS及有机改性的膨润土H,且膨润土在聚合产物中分散性良好;对于PP/PS和PP/(PS/H)共混体系,PS及PS/H的加入影响了PP的结晶形态,使共混体系结晶速率增加,相同比例的共混体系PP/(PS/H)对于PP/PS而言,其熔融峰位置向低温偏移,体系熔点略低,其结晶峰位置向高温偏移,结晶温度有较明显的提高;动态温度扫描结果显示,共混体系的表观粘度随着温度的升高而降低,同等PS含量下,由于杂化体系中膨润土的引入,PP/(PS/H)体系的表观粘度高于PP/PS体系;XRD测试结果表明,在熔融共混加工过程中聚合物链没有插层到膨润土片层中。     

膨润土-PS/PP杂化材料共混体系性能研究

研究了PS/PP、膨润土-PS/PP多元共混体系的性能.结果表明:PS及膨润土-PS的加入影响了PP的结晶形态,使共混体系半结晶时间缩短、结晶速率增加,结晶度降低;PS/PP和膨润土-PS/PP相同比例的共混体系,其熔融峰位置向低温偏移,体系熔点略低,其结晶峰位置向高温偏移,结晶温度有较明显的提高;PP/PS/膨润土共...     

聚丙烯/聚苯乙烯/膨润土共混纤维研究

研究了聚丙烯(PP)纤维可染改性添加剂聚苯乙烯/膨润土(PS/Garamite)杂化复合粒子的原位悬浮聚合及PP/PS/Garamite共混纤维的熔纺成形。对聚合产物中膨润土的层间距、PP/PS/Garamite共混体系中PP的结晶形态、共混纤维的热性能及染色性能进行了表征。结果表明:聚合过程中膨润土的层间距几乎没有变化,添加剂的加入使共混纤维的熔点降低,结晶温度从115℃升高到117℃,结晶度从44.2%降低至40.2%,无定形区域增加。采用分散染料染色,共混改性纤维具有较好的染色深度。     

聚丙烯/凹凸棒土复合材料的结晶行为

通过双螺杆挤出机熔融共混制备了聚丙烯(PP)/凹凸棒土(ATP)复合材料样品,分别采用偏光显微镜和差示扫描量热仪对其结晶行为进行了研究。研究表明,复合材料样品的偏光显微镜照片呈现球晶所特有的十字消光现象,球晶尺寸与纯PP球晶的尺寸相比有所减小。非等温结晶测试结果表明,复合材料样品的结晶温度随着ATP含量的增加向高温方向移动,而且半结晶期缩短,PP/ATP复合材料的总体结晶速率增加;ATP的加入改变了PP成核的机制,起到了异相成核的作用。随着降温速率的增大,PP及PP/ATP(95/5)复合材料的结晶起始温度和结晶峰值温度均向低温方向移动,半结晶期变短。     

复合成核剂对PP/POE共混体系等温结晶行为的影响

以低分子量尼龙6为主体制备了一种新型复合成核剂NF-10,采用差示扫描量热分析仪、偏光显微镜等分析手段研究了该成核剂对聚丙烯/乙烯-辛烯共聚物(PP/POE)共混体系结晶温度、结晶形态、等温结晶及其动力学的影响。结果表明:NF-10可以提高PP/POE体系的结晶温度、结晶度和结晶速率,减小体系结晶球晶的尺寸,提高晶核密度,显著改善PP/POE共混体系结晶性能。     

新型复合成核剂对PP/POE共混物结晶行为的影响

以低分子量聚酰胺6为主体制备了新型复合成核剂,采用高级流变仪、差示扫描量热仪、偏光显微镜等分析手段研究了几种成核剂对聚丙烯/乙烯-1-辛烯共聚物(PP/POE)共混物结晶温度、结晶形态及流变行为的影响。结果表明:新型复合成核剂均可以提高PP/POE共混物的结晶温度、结晶度和结晶速率,减小共混物的球晶尺寸,增加晶核密度,显著提高了PP/POE共混物的结晶性能。     

三元复合聚丙烯共混体系结晶行为及力学性能的研究

本文通过DSC测试得到一些结晶参数,分别对PP/弹性体、PP/弹性体/LLDPE两个共混体系的结晶行为进行了研究。结果表明弹性体对PP成核速率有促进作用:LLDPE与PP是分别结晶的,LLDPE阻碍了PP球晶的生长且破坏了PP球晶的完整性;对PP球晶的插入和分割,使PP球晶有一定的破碎细化。力学性能和加工性能的测定,表明三元共混体系的综合性能优于二元共混体系     

PP/GMS共混物的流动性能及热性能的研究

将聚丙烯(PP)与硬脂酸单甘油酯(GMS)熔融共混,制备不同GMS含量的PP/GMS共混物.采用毛细管流变仪和差示扫描量热仪研究PP/GMS共混物的流变性能和热性能,用偏光显微镜考察共混物的结晶形态和结晶动力学.结果表明:PP/GMS共混物为假塑性流体,GMS可以降低共混体系的表观粘度;共混物的结晶以α晶型为主,GMS...     

降解PP/EPDM共混物的结晶性能研究

采用过氧化二异丙苯(DCP)降解聚丙烯(PP),熔融法制备了降解PP与三元乙丙橡胶(EPDM)共混物,采用差示扫描量热分析(DSC)及广角X射线衍射(WAXD)研究了降解PP/EPDM共混物的结晶行为,结果发现PP降解后β-PP晶型(300)消失 ;降解PP/EPDM共混物的非等温结晶过程是由成核控制的,并伴有明显的快速初级结晶和缓慢的次级结晶过程,降解PP以均相成核的三维球晶方式生长.     

聚丙烯/聚苯乙烯/超支化聚酰胺酯共混物及其纤维性能

以原位悬浮聚合法制备聚苯乙烯/超支化聚酰胺酯(PS/HBP)复合粒子,通过双螺杆共混挤出制备系列聚丙烯(PP)/PS/HBP三元共混物。运用傅里叶变换红外光谱仪对PS/HBP复合粒子进行分析,以偏光显微镜、差示扫描量热仪和锥板流变仪等仪器研究了PP/PS/HBP共混体系的相容性、聚集态结构、结晶性和流变性等性能,以万能材料试验机、红外染色机和电脑测色仪研究纤维的力学性能和染色性能。结果表明:PP、PS为热力学不相容体系,少量HBP的加入即可改变PP球晶结构,使球晶小而密,同时PS均匀分散在PP中;引入HBP使得PP的结晶结构有所完善,结晶温度和结晶度升高;引入PS/HBP复合粒子对PP纤维可纺性影响不大,表现为结构化黏度指数轻微升高,但共混纤维可拉伸性较纯PP有极大提高,力学性能有明显改善,染色性能也有显著提高。     

聚丙烯／聚苯乙烯／膨润土成纤共混体系的性能研究

制备了聚丙烯（PP）纤维可染改性用聚苯乙烯（PS）,膨润土（Garamite）复合粒子。通过扫描电镜（SEM）手段观察PP／PS／Garamite三元共混体系中Garamite的分散情况。对PP／PS／Garamite三元共混体系的力学性能进行了研究,发现随着Garamite含量的增加,共混体系的弹性模量、抗拉强度及断裂伸长率均呈下降趋势。运用ARES型流变仪研究了共混体系的动态流变性能,对进一步研究共混体系的纺丝工艺具有指导意义。     

Crystallization behavior and spherulite growth rate of isotactic polypropylene in isotactic polypropylene/natural rubber based thermoplastic elastomers

The melting and crystallization behavior of isotactic polypropylene/natural rubber (PP/NR) based thermoplastic elastomers (TPEs) were investigated using differential scanning calorimetry. The samples were scanned at a heating rate of 10°C/min under nitrogen atmosphere. The effects of blend ratio on the melting and crystallization characteristics of the blends were analyzed. Normalized crystallinity is unchanged by the addition of small amount of NR, but as the amount of rubber increases crystallinity increased for the 30/70 NR/PP and lowered for the 50/50 NR/PP blend system. Morphology of the blend was analyzed using scanning electron microscopy (SEM). Blend ratio showed a pronounced influence on the phase morphology of the NR/PP TPEs. As the amount of NR increases more than 50 wt % the system changes from dispersed to cocontinuous structure. Hot‐stage polarizing optical microscopy (POM) was used to study the radial growth of spherulite as a function of blend ratio, cooling rate, and crystallization temperature. Spherulite growth rate is marginally influenced by the rubber inclusions. The spherulite morphology observed under polarized optical microscopy is influenced by the blend morphology. It was found that for the cocontinuous 50/50 blend system, spherulites are much different from the usual appearance under polarized light. Attempts have been made to correlate the crystallization behavior with the morphology of the blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Crystallization behavior of polypropylene in polypropylene/nylon 6 blend

This article describes the crystallization behavior of polypropylene (PP) in the presence of a crystallizable polymer, namely, nylon 6, in the binary blend of PP/nylon 6 in the composition range from 0 to 30 wt % of nylon 6 content in the blend. The crystallization behavior was studied through variation of the crystallinity with the blend composition and changes in the crystallization exotherms were recorded by differential scanning calorimetry (DSC) and the spherulite morphology was observed via polarized light microscopy (PLM). Comparison of the crystallization exotherms and melting endotherms revealed some differences which are attributed to the role of a sufficiently high thermal energy of the nylon 6 crystals on the melting of PP. The crystallinity of PP decreased in the presence of nylon 6, whereas the crystallinity of nylon 6 increased considerably in the presence of PP. The rate of nucleation of PP on addition of nylon 6 decreased rapidly in the region 0–10 wt % nylon 6 content, and, thereafter, at a higher nylon 6 content, decrease of the nucleation rate was relatively slow. PLM observation revealed the presence of composite spherulites with PP spherulites grown on the surface of the already‐formed nylon 6 spherulites. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1153–1161, 1999     

Crystallization and dynamic mechanical properties of polypropylene/polystyrene blends modified with maleic anhydride and styrene

Polypropylene (PP)/polystyrene (PS) blends modified with reactive monomers, such as maleic anhydride (MAH) and styrene (St), and in situ formed PP/PS blends were prepared by melting extrusion. The crystallization and melting behavior and the dynamic mechanical properties of the PP/PS blends, including the structure of the grafted copolymer, were investigated with differential scanning calorimetry, dynamic mechanical analysis, and Fourier transform infrared. The results indicated that the addition of MAH hardly influenced the crystallization temperature of PP in the blends, but the addition of MAH and St increased the crystallization temperature of PP in its blends. The blends showed no remarkable variety for the melting temperature, but the shapes of the melting peaks were influenced by the addition of the reactive monomers. In addition, a significant increase in the storage and loss moduli of all the modified PP/PS blends was observed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2038–2045, 2005     

聚乙烯醇/马来酸酐接枝聚丙烯共混物的热行为研究

采用熔融共混法制备了一种聚乙烯醇(PVA)/马来酸酐接枝聚丙烯(PP-g-MAH)共混物膜,通过差示扫描量热仪研究了共混物膜的结晶和熔融行为。结果表明,随着共混物中PP-g-MAH含量（不超过50 %）的增加,PVA相的结晶和熔融温度升高,结晶度增加,结晶速率增加,而随着PVA含量（超过30 %）的增加,PP-g-MAH的结晶及熔融温度降低,结晶度降低,结晶速率增加。用Ozawa法对共混物中PVA相的非等温结晶动力学研究表明,共混物中PVA相在191~197 ℃开始主期结晶,在173~189 ℃进入次期结晶阶段。     

丙烯酸和苯乙烯改性PP/PS结晶与熔融行为

制备了苯乙烯（St）、St与丙烯酸（AA）混合物、丙烯酸接枝聚丙烯（PP-g-AA）改性聚丙烯／聚苯乙烯（PP／PS）共混物以及AA，St改性PP（原位形成PP／PS共混物）。用差示扫描量热仪（DSC）研究了3种改性方法对共混物中PP结晶与熔融行为的影响。结果表明，PS对PP的结晶与熔融温度影响不大，PP-g-AA则提高共混物中PP的结晶温度。St以及St与AA混合单体对PP／PS中PP结晶温度影响不大，但AA改性提高PP／PS中PP结晶温度。St加入PP导致PP结晶温度下降，St与AA混合单体原位聚合则提高PP的结晶温度。改性对共混物中PP的熔融温度影响不大，但是熔融峰形与结晶温度高低有关。红外光谱证实St与AA混合单体改性PP中有PP-g-AA形成，但改性共混物中没有PP-g-AA形成。     

Morphology and thermal properties in the binary blends of poly(propylene-co-ethylene) copolymer and isotactic polypropylene with polyethylene

The morphology and thermal properties of isothermal crystallized binary blends of poly(propylene-co-ethylene) copolymer (PP-co-PE) and isotactic polypropylene (iPP) with low molecular weight polyethylene (PE) were studied with differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), polarized optical microscopy (POM) and wide-angle X-ray diffraction (WAXD). In PP-co-PE/PE binary blends, however, the connected PE acted as a phase separating agent to promote phase separation for PP-co-PE/PE binary blends during crystallization. Therefore, the thermal properties of PP-co-PE/PE presented double melting peaks of PE and a single melting temperature of PP during melting trace; on the other hand, at cooling trace, the connected PE promoted crystallization rate because of enhanced segmental mobility of PP-co-PE during crystallization. At isothermal crystallization temperature between the melting points of iPP and PE, the binary blend was a crystalline/amorphous system resulting in persistent remarkable molten PE separated domains in the broken iPP spherulite. And then, when temperature was quenched to room temperature, the melted PE separated domains were crystallized that presented a crystalline/crystalline system and formed the intra-spherulite segregation morphology: these PE separated domains/droplet crystals contained mixed diluent PE with connected PE components. On the other hand, in the iPP/PE binary blends, the thermal properties showed only single melting peaks for both PE and iPP. Moreover, the glass transition temperature of iPP shifted to lower temperature with increasing PE content, implying that the diluent PE molecules were miscible with iPP to form two interfibrillar segregation morphologies: iPP-rich and PE-rich spherulites. In this work, therefore, we considered that the connected PE in PP-co-PE functioned as an effective phase separating agent for PP and diluent PE may be due to the miscibility between connected PE and diluent PE larger than that between PP and dispersed PE.     

LDPE/EBA共混膜物理力学性能的研究

制备了低密度聚乙烯/乙烯-丙烯酸丁酯(LDPE/EBA)共混膜,并对其结晶性能、力学性能、透气性和透湿性等进行了研究。结果表明:添加EBA后,LDPE/EBA共混体系的初始成核速率和结晶速率降低,形成的球晶体积变小,晶粒尺寸规整性减小,而晶粒数量增多,从而使得LDPE/EBA共混膜的力学性能逐渐降低,气体透过率和透湿率呈增加趋势。