层状分散形态的聚合物共混物

本文综述了聚合物共混物层状分散形态的特征、形成、功能性及具有层状分散形态聚合物共混物的应用领域。     

聚丙烯/聚苯乙烯共混物形态研究进展

从影响因素、晶态变化、界面张力和相容性等方面综述了国内外关于聚丙烯／聚苯乙烯共混物形态的研究进展。聚丙烯／聚苯乙烯共混物的相形态受多种因素的影响,其中混合比例、黏度和界面张力为最关键的因素,影响着共混物的热性能和结晶性能,从而导致相态的各种变化。提出今后应以相容剂研究和相态控制理论研究为重点。     

聚丙烯填充共混物结构与性能的研究

本文研究了ＰＰ／ＢＲ和ＰＰ／ＮＢＲ的ＣａＣＯ３填充共混体系的流变性能、微观结构和机械性能。     

聚丙烯／聚乙烯／顺丁橡胶三元共混物研究

本文研究了取乙烯种类及用量、顺丁橡胶用量、共混方式对聚丙烯／聚乙烯／顺丁橡胶三元共混物性能的影响。结果表明，LLDPE增韧效果优于HDPE。顺丁橡胶用量与共混物的缺口冲击强度成正比关系。采用PE与BR先制备增韧母料的二阶共混方式所得共混物的性能最佳。     

PP熔体接枝物改善HPVC/PP共混物的相容性

采用PP熔体接枝物改善HPVC/PP共混物的相容性。考察了共混比、不饱和极性单体、PP熔体挤出接枝物、增塑剂及EPDM用量对共混物力学性能的影响。     

动态固化聚丙烯／环氧树脂共混物的制备工艺研究

将动态硫化技术应用于热塑性树脂／热固性树脂体系，制备了动态固化聚丙烯／环氧树脂共混物，研究了动态固化PP／环氧树脂共混物制备工艺条件即增容剂、固化剂、环氧树脂的环氧当量及其含量等因素对共混物力学性能的影响。实验结果表明，选择马来酸酐接枝的均聚聚丙烯(PP-g-MAH)作为增容剂，所制得的动态固化PP／环氧树脂共混物的力学性能较好。2-乙基-4-甲基咪唑(EMI-2，4)的适宜用量为1．2％(每100份环氧树脂使用4份)。环氧当量对共混物的性能影响不大。当环氧树脂的含量为5％～10％时，动态固化PP／环氧树脂共混物的综合性能明显好于PP，特别是具有较高的强度和模量。     

溶剂分子透过HDPE/MPA层状共混物的扩散模型

建立了溶剂分子透过聚合物层状共混物的扩散模型 ,给出了溶剂分子相对有效扩散系数D₀ /D与分散相体积分数、不可透薄片形状参数α以及薄片接头缺口参数δ之间的关系式 .经采用不同值及α值共混物得到的实验数据证明 ,该模型与实验结果吻合良好.     

聚丙烯／聚乙烯／顺丁橡胶三元共混物研究

本文研究了聚乙烯种类及用量、顺丁橡胶用量、共混方式对聚丙烯／聚乙烯／顺丁三元共混物性能的影响。结果表明,ＬＬＤＰＥ增韧效果优于ＨＤＰＥ。顺丁橡胶用量与共混物的缺口冲击强度成正比关系。采用ＰＥ与ＢＲ先制备增韧母样的二阶共混方式所得共混物的性能最佳。     

聚丙烯接枝衣康酸增容PA6／PP共混物性能及形态研究

采用反应型双螺杆挤出机和熔融接枝技术制备了一系列聚丙烯（PP）接枝物，包括单一单体接枝物PP接枝衣康酸（PP-g-ITA）和双单体接枝物PP接枝ITA和苯乙烯[PP-g-（ITA-co-St）]，通过红外光谱和热分析研究了PP接枝物的结构，并研究了PP接枝物的接枝率和熔体流动速率与单体和引发剂用量的关系。通过反应挤出制备了PP接枝物增容PA6／PP共混物，研究了增容共混物的力学性能和形态结构。结果显示：加入接枝物后，共混体系的冲击强度明显提高；SEM观察表明，接枝物的加入能明显改善增容共混物的两相界面结合状况，降低共混物的分散相尺寸，改善体系的分散状况，共混物的两相界面变得模糊，相容性得到明显提高；DSC测试表明，加入接枝物后，共混物中PA6组分的结晶度下降，PP组合的结晶度上升。表明PP-g-ITA是PA6／PP共混体系有效的增容剂兼增韧剂。     

聚碳酸酯／聚丙烯共混物的结构与性能

在过氧化二异丙苯的引发下，用反应挤出的方法制备了聚丙烯接枝甲基丙烯酸环氧丙酯。用双螺杆挤出机制务了不同组成的聚碳酸酯／聚丙烯及ＰＣ／ＰＰ－ｇ－ＧＭＡ／ＰＰ的共混物。用电子显微镜观察了不同经组成的形态，与ＰＰ／ＰＣ共混体系相比，ＰＣ／ＰＰ／ＰＰ－ｇ－ＧＭＡ体系中的ＰＣ一ＰＰ中分散相尺寸明显降低，ＰＰ－ｇ－ＧＭＡ加入改变聚丙烯在共混物中的晶体结构及提高了聚丙烯的结晶温度，同时ＰＰ－ｇ－ＧＭＡ的加入对共     

Structure and properties of PP/POE/HDPE blends

This work was aimed to counteract the effect of ethylene‐α‐olefin copolymers (POE) by reinforcing the polypropylene (PP)/POE blends with high density polyethylene (HDPE) particles and, thus, achieved a balance between toughness and strength for the PP/POE/HDPE blends. The results showed that addition of HDPE resulted in an increasing wide stress plateau and more ductile fracture behavior. With the increase of HDPE content, the elongation at break of the blends increased rapidly without obvious decrease of yield strength and Young's modulus, and the notched izod impact strength of the blends can reach as high as 63 kJ/m² at 20 wt % HDPE loading. The storage modulus of PP blends increased and the glass transition temperature of each component of the blends shifted close to each other when HDPE was added. The crystallization of HDPE phase led to an increase of the total crystallinity of the blend. With increasing HDPE content, the dispersed POE particle size was obviously decreased, and the interparticle distance was effectively reduced and the blend rearranged into much more and obvious core‐shell structure. The fracture surface also changed from irregular striation to the regularly distant striations, displaying much obvious character of tough fracture. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

PP/iPB共混物的性能

采用自制的不同熔体流动速率的全同聚1-丁烯(iPB)改性聚丙烯(PP),研究了共混物的力学性能、热性能和结晶性能.结果表明:随着w(iPB)的增加,共混物的冲击强度明显增大,韧性得到改善,而刚性有所下降,共混物的晶体明显细化.     

Morphology and properties of PP/EPDM binary blends and PP/EPDM/nano‐CaCO3 ternary blends

In this article, the morphology, crystallization, and rheological behaviors of polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) binary blend and PP/EPDM/calcium carbonate nanoparticles (nano‐CaCO₃) ternary blend were investigated. Two processing methods, i.e., direct extrusion and two‐step extrusion, were employed to prepare the PP/EPDM/CaCO₃ blend. The influence of EPDM and nano‐CaCO₃ respectively on phase morphology and properties of PP/EPDM blend and PP/EPDM/CaCO₃ blend were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic rheometer. The crystallinity and crystallization temperature of PP/EPDM blend were improved in comparison to pure PP due to addition of EPDM, but kept invariable with the increased EPDM loading. As the EPDM content was increased, the mobility of PP molecular chains was weakened. Compared with direct extruded blend, less and finer nano‐CaCO₃ was dispersed in matrix of two‐step extruded blend. Accordingly, the increased nano‐CaCO₃ in matrix gave rise to a weaker increment in crystallinity and crystallization temperature of two‐step extruded blend, and a later platform of tanδ curve. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical properties and morphology of crosslinked PP/PE blends and PP/PE/propylene–ethylene copolymer blends

Blending is an effective method for improving polymer properties. However, the problem of phase separation often occurs due to incompatibility of homopolymers, which deteriorates the physical properties of polyblends. In this study, isotactic polypropylene was blended with low-density polyethylene. Crosslinking agent and copolymers of propylene and ethylene (either random copolymer or block copolymer) were added to improve the interfacial adhesion of PP/LDPE blends. The tensile strength, heat deflection temperature, and impact strength of these modified PP/PE blends were investigated. The microstructures of polyblends have been studied to interpret the mechanical behavior through dynamic viscoelasticity, wide-angle X-ray diffraction, differential scanning calorimetry, picnometry, and scanning electron microscopy. The properties of crosslinked PP/PE blends were determined by the content of crosslinking agent and processing method. For the material blended by roll, a 2% concentration of peroxide corresponded to a maximum tensile strength and minimum impact strength. However, the mechanical strength of those products blended by extrusion monotonously decreased with increasing peroxide content because of serious degradation. The interfacial adhesion of PP/PE blends could be enhanced by adding random or block copolymer of propylene and ethylene, and the impact strength as well as ductility were greatly improved. Experimental data showed that the impact strength of PP/LDPE/random copolymer ternary blend could reach as high as 33.3 kg · cm/cm; however, its rigidity and tensile strength were inferior to those of PP/LDPE/block copolymer blend.     

Dynamic rheological properties of binary PP/PA and ternary PP/PA/GF blends

The dynamic rheological behavior was investigated for binary polypropylene (PP) - polyamide-6 (PA-6) and ternary PP-PA-6-glass fiber (GF) blends. The observed trends are related to the blend morphology and the partitioning of the GF within the three component blends. The dynamic and shear viscosity results show a good overlap for the PP homopolymer, within the shear rates studied. The addition of PA-6 and/or glass fibers to the PP causes significant deviations between the two rheological behaviors. This reflects the fibrillation of PA-6 and the orientation of glass fibers during shear rheometry, which reduce the blends' shear viscosity. The effect of PA-6 content on dynamic viscosity is less significant than for shear viscosity, owing to the absence of morphological structuring. The addition of PA-6 to PP increased the principal relaxation time of the binary blends. The addition of GF to these binary blends gave a further increase in the principal relaxation time.     

Morphology and elastic properties of PP/EVA polymer blends

Several polypropylene–ethylene vinyl acetate (PP/EVA) copolymers with compositions ranging from 90/10 to 10/90 PP/EVA were prepared and characterized in terms of their morphology by transmission and scanning electron microscopy, and their mechanical properties were also studied. The results show a wide range of spatial structures which correlate well to the corresponding measurements of elastic modulus of the blends.     

动态硫化PP/EPDM共混物的结构与性能

研究了动态硫化和直接共混对聚丙烯／三元乙丙橡胶共混物的力学性能、流动性能和形态结构的影响。结果表明：过氧化二异丙苯（DCP）的加入,使动态硫化和直接共混2种方法制备的共混物的熔体流动速率（MFR）增大,但直接共混的共混物的MFR较动态硫化共混物高。动态硫化共混物的粒径尺寸较直接共混物小,且分布均匀。动态硫化后的共混物中两组分的玻璃化转变温峰接近。DCP的加入使动态硫化共混物的缺口冲击强度明显高于直接共混的共混物。     

Structure and properties of dynamically cured EPDM/PP blends

The structure and properties of polyolefin blends of ethylene–propylene–diene terpolymer (EPDM) and polypropylene were studied. Blends were prepared in a laboratory internal mixer where EPDM was cured with PP under shear with dicumyl peroxide (DCP) at different shear conditions (blend–cure). Blends were also prepared for comparison from EPDM which were dynamically cured in the absence of PP and blended later (cure–blend). The effect of DCP concentration, intensity of the shear mixing, and rubber/plastic composition were studied. In blend–cure, the melt viscosity increased with increasing DCP concentration in blends of 75% EPDM and 25% PP, but it decreased with increasing DCP concentration in blends of 75% PP and 25% EPDM. In cure–blend, however, the melt viscosity increased with increasing DCP concentration for all compositions. The melt viscosity decreased with increasing intensity of the shear mixing presumably due to the formation of the smaller segregated microdomain of the crosslinked EPDM gels in both blend–cure and cure–blend materials. The crystallization rate was higher in EPDM/PP blends than in PP homopolymer. The crystallization rates for various blending conditions were also compared.     

PP/r-PET共混物的力学性能

以聚丙烯（PP）为基础树脂,马来酸酐接枝聚丙烯（PP-g-MAH）为增容剂,用双螺杆挤出机制备PP／PP-g-MAH／回收聚对苯二甲酸乙二酯（r-PET）共混物,研究了r-PET及PP—g-MAH对共混物力学性能的影响。结果表明,加入PP-g-MAH可提高共混体系的相容性,加入r-PET可较大幅度提高PP的弯曲和冲击强度。     

Crystallization of PP in PP/SEBS blends and its correlation with tensile properties

Crystallization of polypropylene (PP) in the blends of PP with styrene–ethylene butylene–styrene triblock copolymer (SEBS) is studied through differential thermal analysis (DTA) and X-ray diffraction measurements. Analysis of crystallization exotherm peaks in terms of crystallization nucleation and growth rates, crystallite size distribution, and crystallinity revealed differences in the morphology of PP component in the blend in the different regions of blend composition. Crystallinity determined by X-ray diffraction and DTA showed identical variations with blend composition. Variations in tensile properties of these blends with blend composition are also reported. Correlations of the various tensile properties with the crystallization parameters, viz., the crystallinity and crystallite size distribution, are presented, which confirm the influence of crystallization of PP component on the tensile properties of these blends.