Surface Modification of Polypropylene by Ethylene Plasma and Its Induced β-Form in Polypropylene

This study aims to investigate the chemical structure and morphology of plasmapolymers produced by deposition of ethylene on the surface of polypropylene. The deposition films(sediments) of ethylene plasma on the surface of polypropylene are nonuniform, and the characterization results indicate the existence of hydroxyl groups and aldehyde(or ketone) groups in the sediments. The sediment of ethylene plasma on the polypropylene surface could induce the growth of β-form crystals in the surface layer of polypropylene.     

聚合物共混相态形成过程及其理论研究进展

聚合物共混过程中相态的形成及变化规律是近年来研究热点问题,这一动态过程将决定静态材料的结构与性能.聚合物共混形态结构发展的机理有初期破碎、中期分散及后期归并等机理.在共混初期,分散相尺寸较大,以细化为主.随着混合时间的增加,分散相逐渐细化,尺寸越来越小,细化也越来越难,在应力场的作用下,分散相粒子可能因碰撞而发生归并,归并与细化将逐渐达到平衡而形成稳定的结构.在混炼后期,剪切力减小,粒子发生有效碰撞归并概率增大.     

Plasma modification of polypropylene surfaces and grafting copolymerization of styrene onto polypropylene

The surface of polypropylene(iPP) is modified with glow discharge plasma of Ar,so that the modified surfaces of iPP films are obtained.The studies of scanning electron microscopy(SEM) show the surface etching pattern of iPP films. The chemical structures of iPP films are confirmed by X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FTIR) spectroscopy.The wetting properties of modified surfaces of iPP films are characterized by contact angle, and the free energy of surfaces is calculated.The free radical of modification surfaces of iPP is measured by chemical method.The surfaces of iPP are achieved with Ar plasma treatment followed by grafting copolymerization with styrene(St) in St.The grafting polymer of St onto iPP is characterized by FTIR.The grafting rate is dependent on plasma exposure time and discharge voltage.The studies show that homopolymerization of St is undergone at the same time during the grafting-copolymerization of St onto iPP.     

Shear-induced crystallization in phase-separated blends of isotactic polypropylene with ethylene-propylene-diene terpolymer

The compatibility between isotactic polypropylene(i PP) and ethylene-propylene-diene terpolymer(EPDM) in the blends was studied. SAXS analysis indicates that i PP and EPDM phases in the binary blend are incompatible. Isothermal crystallization behaviors of i PP in phase-separated i PP/EPDM were studied by in situ POM equipped with a Linkam shear hot stage. It was found that typical spherulites of i PP were formed both in neat i PP and in i PP/EPDM blends. The radial growth rate(d R/dt) of spherulites of i PP in the blend was not influenced by EPDM phases. Further investigations on isothermal crystallization of i PP in i PP/EPDM after shear with a fixed shear time showed that the crystallization rate of i PP in the blends increased with increasing shear rates, whereas, the crystallization rate was much lower than that of neat i PP. WAXD results showed that ?-crystal i PP was formed in neat i PP as well as in i PP/EPDM blends after shearing and the percentage of ?-crystal bore a relationship to the applied shear rate. The presence of EPDM resulted in lower percentage of ?-crystal in the blends than that in neat i PP under the same constant shear conditions. SAXS experiments revealed that shear flow could induce formation of oriented lamellae in i PP and i PP in the blends, and the presence of EPDM led to a reduced fraction of oriented lamellae.     

小角X光散射法研究聚丙烯/乙丙橡胶合金的相结构

用X光小角散射和扫描电子显微镜研究了聚丙烯 乙丙橡胶合金薄膜 .根据Debye Buech光散射统计理论计算了结构参数 ,即相关函数ac、平均弦长 l和旋转半径Rg.同时计算了Porod指数α ,并用α讨论了分散相的形状 .用扫描电子显微镜观察了共混物的形态和结构     

Investigations on structure and properties of blends of polypropylene with polyamide 1010 by Rayleigh scattering

The phase structure and morphology of polypropylene （iPP） blends with poly（decamethylene sebacamide （polyamide 1010, PA 1010） and the part-compatible alloys （iPP/PA 1010/iPP-g-MAH） are investigated by Rayleigh scattering, i.e. small angle light scattering （SALS）. The structure parameters of SALS, i.e. correlation distance, ac and average chord lengths, /, are calculated. Their variation with the composition of the blends and alloys is discussed. The morphology and structure of fracture surfaces in the blends and alloys are studied by SEM images. The average diameter of dispersed phase in the blends and alloys is calculated by graph processing. The variation of average diameter is similar as that of average chord lengths of dispersed phases. The mechanical properties of the blends and alloys are analyzed and the relation of modulus and yield stress with the composition is studied. It is confirmed that the correlation between the modulus and the structure parameters is non-linear, while the correlation between the yield stress and the composition or structure parameters is linear.     

等离子体条件下PP／PS共混体系组成和相结构的关系

运用等离子体装置制备了聚苯乙烯预聚物(PSt)并对聚丙烯(PP)进行了表面处理,得到改性聚丙烯(gPP)。在密炼机中以间歇出料法制备了不同组成的聚丙烯(PP)/聚苯乙烯(PSt)和改性聚丙烯(gPP)/聚苯乙烯(PSt)共混物。针对扫描电镜图样,用投影面直径dp这一结构参数研究了组成对两个共混体系相尺寸的影响以及相应的相分散状况。利用分布函数求取了分散相聚苯乙烯(PSt)分形维数,对不同组成的相分散进行了研究。     

显微镜图像分析研究非相容高密度聚乙烯/尼龙1010共混体系熔体动态过程中相结构的形成与发展

讨论了非相容高密度聚乙烯,尼龙1010共混体系在熔融混炼过程中相结构的形成与发展.应用在线连续采样方法,获得共混过程中体系不同时刻的样品,应用扫描电子显微镜观察并得到共混物相结构的显微图像.用图像处理和图估计方法求得了体系分散相平均粒径和粒径分布宽度,讨论了平均粒径和分布宽度随混炼时间的变化.结果表明,共混物相结构的变化主要发生在混炼初期,即混炼两分钟以前,之后平均粒径和分布宽度趋于平稳,保持在一定数值范围内.引入分性概念,应用测度法计算了体系的分形维数,表明体系相结构的变化具有自相似性,分形维数的变化与体系的均匀性有关.同时,研究了混炼温度和混炼设备的转速(剪切速率)与体系分散相平均粒径、分布宽度和分形维数等结构参数的关系.     

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.