共聚PP/POE共混物流变行为的研究

采用XLY-Ⅱ型毛细管流变仪研究了共聚聚丙烯(iPP)、乙烯-辛烯共聚物(POE)及其共混物的流变特性.实验结果表明,PP/POE共混物的最佳加工温度为180℃.iPP/POE共混物熔体均为假塑性流体,呈现出切力变稀现象.PP/POE复合材料的表观黏度与粘流活化能均随着POE含量的增加而减小.     

CPE对PVC／PP体系流变性能的影响

利用Instron毛细管流变仪对PVC/PP及PVC/PP/CPE共混体系的流变性能进行了细致的考察。结果发现,增容剂CPE对PVC/PP体系的流变性能起着双重作用。一方面,在PVC/PP共混物为“海-岛”结构时,CPE起着作为橡胶的增粘效应;另一方面,在PVC/PP共混物为“互锁”结构时,CPE的润滑增塑效应使得它起着降低“互锁”共混物熔体粘度、提高成型加工性能的作用。     

胍基聚电解质与聚丙烯共混体系的流变性能研究(Ⅰ)PHGC/PP

以毛细管流变仪研究了不同组成的 PHGC/ PP共混体系的熔体流变行为 ,分别讨论了熔体粘度与温度、共混体系组成之间的关系 ,并在电镜下观察了共混体系的相态结构 ,分析了共混体系的相容性对熔体流变行为的影响。结果表明 ,在实验条件下 ,PHGC/ PP共混体系为切力变稀型流体 ;PHGC与 PP相容性较差 ,在 PP中分散颗粒较大 ;PHGC含量较低时 ,熔体粘度有极小值 ,随着温度和剪切速率的变化 ,熔体粘度随 PHGC含量的变化呈现出不同的变化趋势。在 PHGC含量为 2 .5 %时 ,非牛顿指数最大 ,粘流活化能最小     

双峰中密度聚乙烯/高压聚乙烯共混物的流变行为与力学性能

用毛细管流变仪研究了双峰中密度聚乙烯(BMDPE)及其与高压聚乙烯(LDPE)共混物熔体的流变行为。讨论了共混物的组成、剪切应力、剪切速率及温度对熔体流变行为的影响和挤出膨胀比，测定了不同配比熔体的非牛顿指数(n)，熔融指数(MI)。测定了共混物的屈服应力、断裂应力和断裂伸长率。证明共混物的强度随双峰中密度聚乙烯含量的增加而提高，为BMDPE的加工和使用提供了依据。     

胍基聚电解质与聚丙烯共混体系的流变性能研究(I)PHGC/PP

以毛细管流变仪研究了不同组成的PHGC／PC共混体系的熔体流变行为,分别讨论了熔体粘度与温度、共聚体系组成之间的关系,并在电镜下观察了共混体系的相态结构,分析了共混体系的相容性对熔体流变行为的影响。结果表明,在实验条件下,PHGC／PP共混体系为切力变稀型流体;PHGC与PP相容性较差,在PP中分散颗粒较大;PHGC含量较低时,熔体粘度有极小值,随着温度和剪切速率的变化,熔体粘度随HGC含量的变化呈现出不同的变化趋势。在PHGC含量为2．5％时,非牛顿指数最大,粘流活化能最小。     

胍基聚电解质与聚丙烯共混体系的流变性能研究(Ⅱ)PHGS/PP

以毛细管流变仪研究了不同组成的PHGS/PP共混体系的熔体流变行为，分别讨论了熔体粘度与温度、共混体系组成之间的关系，并在电镜下观察下共混体系的相态结构，分析了共混体系的相容性对熔体流变行为的影响。结果表明，在实际条件下，PHGS/PP共混体系为切力变稀型流体；PHGS以细小均匀的颗粒分散在PP中，PHGS/PP共混体系，在高剪切速率区，随着PHGS含量的增加，熔体粘度减小，在低剪切速率区，PHGS含量为2.5%时，熔体粘度有极大值，非牛顿指数在PHGS含量为2.5%时有极小值，而在含量为5.0%时有极大值，粘流活化能在PHGS含量为2.5%时最大。     

云母/聚丙烯共混物熔体的拉伸流变性能

采用双料筒毛细管流变仪和Haul-off牵伸设备, 研究了云母(Mica)/聚丙烯(PP)共混物在拉伸流场中的流变性能。结果表明: Mica/PP共混物熔体拉伸流动属于拉伸变稀型, 随着云母含量的增加, 熔体的表观拉伸黏度逐渐增大。熔体的拉伸应力和表观拉伸黏度均随温度的升高而下降。随着拉伸应变速率的提高, 熔体的拉伸应力增大, 表观拉伸黏度减小, 熔体拉伸流动活化能呈下降趋势。云母微粒的加入使聚丙烯熔体的拉伸模量明显增大, 但随着拉伸速度的提高, 共混熔体的拉伸模量下降显著。为了提高Mica/PP共混物的纺丝稳定性, 应严格控制好拉伸速度和加工温度。     

PEG及其复合加工助剂对UHMWPE/PP共混物流变性能的影响

用高压毛细管流变仪研究了PEG、PEG与硅藻土和玻璃微珠的复合物对UHMWPE／PP(80／20)共混物加工流变性的影响,结果表明,少量PEG及其复合加工助荆均能显著降低UHMWPE／PP的熔体表现粘度,改善挤出物的外观质量。PEG与玻璃微珠对UHMWPE／PP熔体有协同降粘作用。     

超声作用下PP／POE共混体系结构与性能研究

研究了超声辐照作用下PP／POE共混体系的挤出加工流变行为、力学性能及结晶行为的影响。结果表明：在超声辐照作用卞PP／POE共混体系的熔体表观黏度随超声功率的增加而减小,超声辐照能降低口模压力,提高挤出物产量。适宜功率的超声辐照有助POE粒子的破碎和在PP基体中的均匀分散,改善二者相容性,提高了共混体系的冲击性能。     

超声辐照作用下PP/POE共混体系结构与性能的研究

研究了超声辐照对PP/POE共混体系的挤出加工流变行为、力学性能及结晶行为的影响。结果表明:在超声辐照作用下PP/POE共混体系的熔体表观黏度随超声功率的增加而减小,超声辐照能降低口模压力,提高挤出物产量。适宜功率的超声辐照有助于POE粒子的破碎和在PP基体中的均匀分散,改善二者相容性,提高了共混体系的冲击性能。     

Effect of blend composition on the rheology property of polypropylene/poly (ethylene-1-octene) blends

In the present study, the dynamic viscoelastic properties for binary blends consisting of polypropylene (PP) and poly (ethylene-1-octene) (POE) were investigated using a Stresstech Rheometer in molten states at 210 °C. The results show that the blends with different content of POE present diversified rheological behaviors. Meanwhile, the blends with 10 wt% and 20 wt% POE show especial rheological behaviors. The dynamic complex viscosity of the blends with 10 wt% and 20 wt% POE are higher than that of others. The storage modulus and loss modulus of the blends with 10–40 wt% POE are different from other blends, and the blends with 10 wt% POE present the largest relaxation time. This behavior is probably related to the miscibility and long chain branch of POE in the PP/POE blends.     

miPP/ziPP共混体系的流动性能

首次对茂金属聚丙烯(miPP)／齐格勒-纳塔聚丙烯(ziPP)共混体系的流动性进行了系统的研究。研究发现，在miPP／ziPP共混体系中，miPP含量的变化改变了共混体系的相结构，这种相结构会随着温度和剪切速率的变化而产生明显的变化，从而改变了体系的流动性能，且该共混体系在不同剪切速率下的流动曲线可以分别通过两个模型进行模拟。     

V-POSS/MPE共混熔体的流变行为与力学性能

为研究笼型倍半硅氧烷(POSS)对茂金属聚乙烯(MPE)的改性作用,用毛细管流变仪研究了MPE与乙烯基笼型倍半硅氧烷(V-POSS)共混物熔体的流变行为;讨论了共混物组成、剪切应力、切变速率及温度对熔体流变性、非牛顿指数和挤出膨胀比及力学性能的影响。结果表明,加入V-POSS熔体的流动性随切应力增大而变好,假塑性增强,挤出膨胀比降低。在V-POSS的含量>2%后,非牛顿指数n值在0.50～0.55之间波动。V-POSS在共混体系中有增塑和交联剂两种作用,V-POSS含量为2%时共混物力学性能最佳。     

多单体熔融接枝PP增容PP/PVC共混体系的力学和流变性能研究

合成了一种新型的多单体接枝物PP－g-(St-co-MMA),研究了其对PP／PVC共混体系的增容作用。讨论了接枝物用量对共混物力学性能和流变行为的影响，并通过扫描电镜（SEM）对共混物的亚微观相结构进行了分析。结果表明，该接枝物对PP／PVC共混体系有较好的增容效果，材料的力学性能在接枝物用量为6份时出现峰值；加入接枝物能使体系的熔体粘度增加，并且在所研究的温度和压力范围内共混物熔体呈典型的假设性流体特性。     

SiO_2包覆改性纳米TiO_2粒子对聚丙烯拉伸流变性能和结晶行为的影响

为了探究光催化功能性聚丙烯(PP)纤维的可纺性及加工性能,首先以SiO2包覆改性纳米TiO2粒子(SiO2@TiO2)为添加剂,对PP进行共混改性。然后,用毛细管流变仪测试了SiO2@TiO2/PP共混熔体的拉伸流变性能,用XRD和DSC研究了SiO2@TiO2对PP性能的影响。结果表明:SiO2@TiO2/PP共混熔体属于拉伸变稀型流体。熔体的拉伸应力和拉伸黏度均随温度的升高而下降;拉伸黏度随添加剂用量的增加而增大,拉伸流动活化能随拉伸应变速率的提高而降低。SiO2@TiO2的加入不会明显改变PP的结晶结构,但会使结晶性能增强,当SiO2@TiO2的含量为4wt%时,共混熔体的结晶度比纯PP的高8.6%。SiO2@TiO2能使PP形成更为紧密的晶体结构,这对材料的性能具有重要影响。     

EPDM磺酸锌盐及其与HDPE共混物形态结构和流变行为的研究

本文通过TEM和毛细管流变仪对EPDM磺酸盐及其与HDPE共混物形态结构和流变行为进行了研究。实验结果表明,随磺化度的增大,离子聚集更为明显,EPDM磺酸盐的熔体表观粘度显著增加,导致共混物熔体表观粘度增加。经硬脂酸锌(ZnSt)增塑后,EPDM磺酸锌盐(Zn-SEPDM)熔体表观粘度将下降,通过加入ZnSt可望改善HDPE/Zn-SEPDM的加工性能。     

Blends of PP/PE co‐octene for modified atmosphere packaging applications

The aim of this work was to obtain films of polypropylene (PP)/polyethylene co‐octene (POE) blends and study the influence of their composition and mixing conditions on final morphology and ultimate properties (thermal, mechanical, oxygen and water vapour transmission rates). Scanning electron microscopy showed segregation of POE domains in the PP matrix. Thermal analysis indicated that the addition of POE modified neither the melting temperature nor the crystallinity of PP in the pressed films. It was found that permeabilities of films were mainly related to POE content rather than morphological features. For the maximum POE concentration used (40%), the oxygen permeability increased up to ∼100% from that of neat PP. A similar trend was found for water vapour permeability. Rigidity of blends dropped significantly with the addition of POE although their ductility slightly increased when compared to pure PP. No significant effect of blend preparation conditions on these properties was found. Mechanical and permeability characteristics of films make them very attractive to be used for MAP of fresh produce such as apple, blueberry and mushroom. Copyright © 2011 John Wiley & Sons, Ltd.     

Microstructural,thermal and rheological correlations to mechanical response of polyamide-6(glass filled)/polyetherimide blend: effect of ethylene-octene copolymer on toughening of blend

Melt mixed glass-filled polyamide 6(PA6)/polyetherimide (PEI) blends were prepared in a co-rotating twin screw extruder over the entire composition range of 0–100 wt% of polyamide 6. These blends were characterized by structural, rheological, mechanical and thermal properties. Crystallization behavior and phase morphology of the blends were also investigated. The blend with the composition PA6/PEI 75/25 showed overall improved mechanical properties along with low resultant viscosity which can be processed on standard equipment. Shear viscosity along with shear stress of the blends were analyzed using shear rheometer which concluded that the blends can be processed on standard equipment due to resultant low viscosity. Scanning electron microscope micrographs revealed that the morphology of the blends showed a two phase structure in which the minor phase was dispersed as domains in the continuous phase. Polyolefin elastomer (POE) as impact modifier was added to the above composition in the range of 0–15 phr to study its effect. The thermal characteristics of PA6, PEI, and PA6/PEI blends with and without POE were investigated using DSC and TGA which revealed that the melting temperature and crystallization temperature of the blend remained unchanged while XRD results showed percent crystallinity was increased slightly. Furthermore, it can be said that the blend with composition PA6/PEI 75/25 with 10 phr impact modifier loading was suitable for high end applications because it combines the high mechanical properties of glass-filled PA6 with inherent flame-retardant property of PEI while POE overcomes the physical weakness of moisture absorption.     

N-苯基马来酰亚胺／甲基丙烯酸甲酯／苯乙烯乳液共聚物与PVC共混的研究

通过乳液共聚合的方法合成了N-苯基马来酰亚胺/甲基丙烯酸甲酯/苯惭纳三元共聚物,将其与PVC共混得到耐热PVC共混物,研究了共聚物组分含量对PVC共混物的力学性能,流变性的影响,用TBA,TGA对共混物的耐热性进行了表征,同时考察了共混物的微观结构与形态。