EFFECT OF DRAWING ON MORPHOLOGY,STRUCTURE AND MECHANICAL PROPERTIES OF BLENDS OF A LIQUID CRYSTALLINE POLYMER AND MODIFIED POLY(PHENYLENE OXIDE)

Polymer strands with various draw ratios of a thermotropic liquid crystalline polymer (LCP) and modified poly(phenylene oxide) were prepared by drawing the melts leaving a slit die in open air. The morphology, structure and mechanical properties of the resulting strands were studied as a function of LCP content and draw ratio. It was found that the thermal and mechanical properties of the matrix phase did not change dramatically with the amount of LCP and draw ratio, but the orientation of LCP phase could be increased with draw ratio. The mechanical properties of the strands could be improved by moderately drawing the melts. Wide angle X-ray diffraction suggested that the improvement in tensile strength of the strands was due to the resultant fibrillation of LCP phase and enhanced molecular orientation. Morphological observation indicated that excessive drawing of the strands could lead to the break down of the microfibrils of LCP and thus resulted in the decrease of mechanical strength.

Polymer Modified Concrete of Blended Cement and Natural Latex Copolymer: Static and Dynamic Analysis

This paper deals with the effect of blended cement and natural latex copolymer to static and dynamic properties of polymer modified concrete. The polymer was used copolymer of natural latex methacrylate (KOLAM) and copolymer of natural latex styrene (KOLAS) with composition of 1%, 5%, and 10% w/w of weight of blended cement in concrete mixture. They are tested for compressive strength, flexural strength, splitting tensile strength, and modulus elasticity for static analysis, and impact load and energy dissipation profile for dynamic analysis. The result shows that KOLAM with concentration 1% give better performance in static and dynamic properties. The KOLAM 1% gives improvement in flexural strength, splitting tensile strength and modulus elasticity about 4%, 13% and 3% compared to normal concrete. And for dynamic properties, KOLAM 1% could reduce impact load up to 35% and improve energy dissipation capacity about 45% compared to normal concrete. The concentration of KOLAM higher than 1% resulting negative effect to static and dynamic properties, except modulus of elasticity. For KOLAS, there were no positive trends of static and dynamic properties.

“Cutting effect” of organoclay platelets in compatibilizing immiscible polypropylene/polystyrene blends

In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.

A DYNAMIC MECHANICAL ANALYSIS STUDY OF THE TRANSITION BEHAVIOUR OF I-PP/EPDM BLENDS

The transition behaviour of the blends of isotactic polypropylene (i-PP) with ethylene-propylene terpolymer (EPDM) containing 42 wt% propylene was investigated by dynamic mechanical analysis technique (DMA). Owing to its high propylene content, EPDM is compatible with i-PP to some degree. The interaction between the two components was strengthened. As expected, for partially compatible system the glass transition temperature of i-PP in the blends shifted to lower temperature. It was found that there existed two transitions, αEPDM and βEPDM, for the EPDM used in this work. The former was considered to be the glass transition of the random chain segments of EPDM, while the latter the local motion of the long ethylene sequences in EPDM. The unusual transition behaviour of αEPDM in the blends was explained in terms of the greater thermal expansion of EPDM and the compatibility of the two components. On the other hand, the βEPDM changed with the composition of the blends in a regular manner.

废弃聚乙烯、废弃聚丙烯改性沥青的研究进展

综述了近年来废弃聚乙烯(RPE)、废弃聚丙烯(RPP)及其共混物(RPE/RPP)改性沥青的研究进展,总结分析了三大类改性剂所存在的优缺点,并对废弃塑料改性剂未来发展的趋势进行了展望。

废弃聚乙烯/废弃聚丙烯共混物功能化改性沥青混合料性能研究

通过双螺杆挤出分区加料技术制备三元共混改性剂(TBM),其中废弃聚乙烯/废弃聚丙烯/聚丙烯接枝马来酸酐(RPE/RPP/PP-g-MAH)质量比为6/4/0.7;以AC-20基质沥青混合料质量的0.4%添加TBM,研究了不同湿拌和时间、不同拌合温度对AC-20改性沥青混合料动稳定度影响,分析了不同拌合时间对TBM在改性沥青混合料中的形态变化的影响,比较了0、0.2%、0.3%、0.4%、0.5%TBM含量(以AC-20基质沥青混合料质量计)对AC-20改性沥青混合料高低温性的影响。结果表明,在干拌和工艺条件下,干拌和时间30 s,湿拌和时间不低于180 s且湿拌和温度为170℃时高温性能最佳,且TBM改性AC-20中其最佳含量为0.4%。

聚丙烯/羟基化聚丙烯共混膜的增容

采用乙醇和乙二胺对马来酸酐接枝聚丙烯(PP-g-MAH)分别进行酯化和酰胺化,得到酯化的马来酸酐接枝聚丙烯(PP-g-MAHOR)和酰胺化的马来酸酐接枝聚丙烯(PP-g-MAHNH_(2)),并将其并作为聚丙烯(PP)和羟基化聚丙烯(PPOH)熔融共混的增容剂。采用双螺杆挤出机共混制得流延膜,对其表面形貌、力学性能、亲水性能、热稳定性和流变性能进行了表征。结果表明:采用PP-g-MAHNH_(2)作为增容剂的共混膜PPOH团聚颗粒最小,且共混膜的亲水性最好,断裂伸长率和断裂强度最高,同时弹性回复率最高。当PP、PPOH和PP-g-MAHNH_(2)的质量比是90∶10∶5时,共混膜的断裂伸长率和断裂强度分别为370%和38.4 MPa,水接触角为87.4°,且该功能化增容剂的加入不影响共混膜的热稳定性。

Preparation of Polypropylene/Poly(styrene-co-(butyl methacrylate)) Nanoblends by Diffusion and Subsequent Copolymerization of Monomers in Isotactic Polypropylene Pellets

The diffusion and subsequent copolymerization of styrene （St）/butyl methacrylate （BMA） mixed monomers in iPP pellets to prepare copolymer nanoblends were investigated. The diffusion step was carded out at 90 ℃ for 2 h in water, and the copolymerization was initiated by the addition of BPO with the aid of a small amount of St. The diametrical distributions of both St and BMA units and their ratio St/BMA were investigated by micro FTIR. Both St and BMA can diffuse into the centres of iPP pellets. The diametrical distribution of St/BMA ratio is constant in all the copolymer blends. The copolymer composition depends on the comonomer feed ratio. The molecular weights of the copolymers were measured by GPC after extraction with tetrahydrofuran. The phase morphology of the copolymer blends was investigated by FESEM, showing the average particle sizes of less than 100 nm. DSC measurements show that the diffusion and subsequent copolymerization of St/BMA monomers only occur in the amorphous regions of iPP pellets.

Chemical-physical aspects of formation and evolution of phase structure in multi-polymers: Intensity fluctuation, phase structure and its fractal characteristics in blends of isotactic polypropylene with poly(cis-1,4-butadiene) rubber

This paper studies the formation and evolution of phase structure of isotactic polypropylene/poly(cis-1,4-butadiene) (iPP/PcBR) blends during molten and mixing in a visual mixer by on-line analysis of the small angle light back scattering. The density fluctuation of iPP/PcBR blends during molten and mixing is discussed using the integral-intensity Js, of the scattering intensity of the blends. The "invariant" Q, which shows fluctuation of the system, is calculated by data of the small angle light back scattering, and the variation of Q with the blending time, temperature and shear rate during molten and mixing in iPP/PcBR blends is discussed. The structure parameters which characterize dimensions of phase in the blends, as the correlation distance ac, and the average chord lengths of two-phase, as li PP and lP cBR, are calculated by data of scattering intensity. The average diameters dp of dispersed phases are calculated from SEM images. The variation of ac, dp, li PP and lP cBR with the blending time and compositions in the blends during molten and mixing is discussed. The scale law is analyzed to find multi-scale characteristics in this system. The generalized fractal dimension Dp is calculated and the relation of Dp with generalized entropy function is discussed to determine that Dp is state function and the physical significance of Dp is the same as that of the generalized entropy function.

EPDM/PP热塑性动态硫化胶的进展

阐述了 EPDM/PP共混型热塑性动态硫化胶的发展历史、制备工艺、微观相态结构、性能、加工技术和应用领域。

超支化聚合物在树脂改性中的应用研究进展

超支化聚合物因其独特的结构和性能特点,已在众多领域得到应用,特别是在树脂改性中的研究发展迅速。综述了超支化聚合物作为树脂改性剂在聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、聚碳酸酯、尼龙6等热塑性树脂和环氧树脂、不饱和聚酯树脂、乙烯基酯树脂等热固性树脂中的应用研究进展,超支化聚合物可作为热塑性树脂的加工助剂、流变学改性剂、增容剂或增强剂以及热固性树脂的增韧剂。同时对超支化聚合物在树脂改性中的应用研究方向做出了展望。

聚丙烯／聚对苯二甲酸乙二酯共混自增强材料的研究

聚丙烯／聚对苯二甲酸乙二酯共混自增强材料的研究陈鸣才，黄玉惠，赵树录，廖兵，林果，丛广民（中国科学院广州化学研究所广州５１０６５０）关键词聚丙烯，聚对苯二甲酸乙二酯，高分子共混物，自增强材料聚对苯二甲酸乙二酯（ＰＥＴ）具有良好的成纤性和透明性，但收缩...

聚丙烯混杂复合体系的界面和力学性能

从刚性粒子增韧聚合物体系的界面层性质入手，研究了带有柔性分子链界面改性剂包覆的高岭土（Ｋａｏｌｉｎ）刚性粒子增韧的，短切玻纤（ＧＦ）增强的聚丙烯（ＰＰ）混杂复合体系的微观结构，结晶性质，ＰＰ／Ｋａｏｌｉｎ／ＧＦ混杂复合材料的加工流动性及力学性能．实验结果表明，所合成的界面改性剂对ＰＰ／Ｋａｏｌｉｎ复合材料有显著的增韧效果；加入少量的短切玻纤可以弥补因界面改性剂引入而引起的ＰＰ／Ｋａｏｌｉｎ复合材料强度和模量降低的缺点；经界面改性剂包覆的高岭土刚性粒子和短切玻纤同时加入ＰＰ，混杂复合后，ＰＰ复合材料的冲击韧性大幅度提高，材料的强度和模量不降低．这个结果不仅在较低的Ｋａｏｌｉｎ含量下。

改性聚丙烯纤维的染色性

将ＲＳＭ－１和Ｅ与聚丙烯共混，制得分散染料可染改性聚丙烯纤维．讨论了共混物组分和组成对共混纤维染色性能的影响．结果表明，ＲＳＭ－１和Ｅ对提高改性聚丙烯纤维的染色性均有明显效果．

显微镜图像分析研究聚丙烯/尼龙1010共混物相结构及其性能

用扫描电子显微镜图像分析研究了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态结构,计算了表征相结构和尺寸的结构参数,如分散相的平均直径、平均弦长和分散相的质心相关距等.并分别讨论了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态以及其结构参数与共混物组成的关系.测定了聚合物及其共混物体系的力学性能,讨论了共混物组成与力学性能的关系.聚丙烯/聚酰胺1010共混物的拉伸模量与组成的关系较为复杂,但其部分相容体系的拉伸模量与组成呈线性关系.聚丙烯/聚酰胺1010及其共混物体系的屈服强度与共混物组成均呈线性关系.表征相结构的两相平均弦长比(l-1/-l2)与组成以及共混物体系力学性能与组成的关系,二者相似.同时讨论了体系力学性能随相尺寸等的变化规律.

mPP对PP/TLCP共混物结晶行为的影响

探讨了聚丙烯马来酸酐接枝共聚物对热致液晶共聚酯与聚丙烯共混物的等温和非等温结晶行为的影响。研究结果表明 ,该共聚物强化了热致液晶共聚酯和聚丙烯的相间联系 ,结晶速度提高、结晶温度提前。

聚丙烯增强增韧进展

论述了超高分子量聚乙烯、液晶高分子、晶须和纳米材料对聚丙烯(PP)的增强增韧改性,并介绍了改性聚丙烯的性能和改性机理。

超活性Z-N催化剂催化丙烯聚合的粒子形态研究

研究了高效负载型齐格勒—纳塔催化剂在不同条件下进行丙烯本体聚合时的复形情况。研究发现催化剂在淤浆预聚后再进行丙烯本体聚合所得到的聚合物粒子有较好的形态和分布，同时也发现预聚时引入长链 α烯烃单体可有效地降低聚合物的表观密度，这对于共聚时生成聚合物合金十分有利。

茂金属聚乙烯弹性体和三元乙丙橡胶增韧聚丙烯的比较

用茂金属聚乙烯弹性体mPE代替三元乙丙橡胶EPDM对聚丙烯PP增韧改性并进行了比较。结果表明,mPE共聚物中的辛烯质量分数越高,其对PP的增韧效果越好;随着共混物中弹性体质量分数的增加,共混物的拉伸强度和弹性模量降低,扯断伸长率增大。PP/mPE与PP/EPDM增韧体系相比,二者的拉伸强度差别不大,但PP/mPE的弹性模量和扯断伸长率稍低;与EPDM相比,mPE对PP具有较好的增韧效果,含有质量分数40%mPE的共混物试样在-30°C下的缺口冲击强度已超过纯PP的20倍,约是相同弹性体质量分数PP/EPDM的近9倍。另外,PP/mPE还具有较低的拉伸永久变形、压缩永久变形和蠕变变形。