PP/PVC/PP-g-(St-co-MMA)的形态结构

以苯乙烯一甲基丙烯酸甲酯共聚物接枝聚丙烯[PP—g-（St—co—MMA）]为相容剂，利用扫描电子显微镜（SEM）和x射线能谱仪（EDS）对PP／PVC／PP—g-（St—co-MMA）的形态结构进行了研究。由x射线能谱微区分析得到了共混物中氯元素面分布图，对氯元素面分布进行了粒径统计。结果表明，在PP／PVC中加入PP-g-（St—co—MMA）相容剂，共混物亚微观相形态结构发生了变化。PP—g-（St—co—MMA）能够明显降低PP／PVC共混物中PVC分散相的分散尺寸，提高共混物两相之间的相容性。改变相容剂的用量和共混物的组成，都对体系的形态结构产生影响。     

改性透明聚丙烯

主要介绍了聚丙烯透明改性的基本原理、透明剂的合成以及聚丙烯的透明改性方法和工艺过程 ,对聚丙烯透明改性的国内外研究现状进行了评述 ,并以山梨糖醇衍生物透明成核剂为主简述了透明聚丙烯的加工过程、性能和应用     

超声挤出DP/纳米SiO2复合材料的拉伸与流变性能

在高能超声波作用下,将纳米SiO2和一种新颖的共聚聚丙烯(DP)熔融共混,制备纳米复合材料,研究了纳米SiO2含量和超声波对复合材料拉伸和流变性能,以及脆断面形貌的影响。结果表明,低含量(≤2%)纳米SiO2对DP有增强作用,随着填料含量增加断裂强度下降。超声波的引入能提高含量较高SiO2(>2%)的复合材料的断裂强度和断裂伸长率,降低体系黏度,并有助于纳米SiO2在DP基体中均匀分散。     

界面改性剂对PP/滑石粉形态结构和性能影响

用在50L固相接枝反应器中合成的等规聚丙烯接枝马来酸酐(PP-g—MAH)作界面改性剂，制备了PP—g—MAH／PP／滑石粉复合材料。研究了PP—g—MAH／PP／滑石粉复合材料的形态结构和力学性能。结果表明，PP—g—MAH对PP／滑石粉复合物的缺口冲击强度、弯曲强度和拉伸强度均有增强作用；PP—g—MAH对PP／滑石粉复合物表观粘度几乎没有影响。SEM观察发现PP—g—MAH对PP／滑石粉复合物相界面有明显的改善。     

聚丙烯熔融特性与MDSC条件的相关性

用调制式差示扫描量热法研究了聚丙烯(PP)升温过程熔融特性与线性升温速率（β)、温度调制振幅（AT)和调制周期(p)的相关性。实验结果表明，在低β时，总热流部分PP熔融呈现双峰；β加快时，呈现单熔融峰。随β加快，不可逆热流部分熔融热(△H)增加；可逆热流部分出现明显的放热峰。随p延长，总热流部分和不可逆热流部分的熔融峰温(Tp)基本不变，起始熔融温度(Ton)降低；但△H前者不变，后者增加；可逆热流部分从吸热变成放热，放热峰温移向高温。总热流和不可逆热流部分的Tp和Ton不受AT的影响，但随AT增大△H前者不变，后者降低。     

聚乙烯与聚丙烯单组分复合材料研究进展

综述了聚乙烯、聚丙烯单组分复合材料的发展概况及最新研究动态。介绍了熔融膜压法、粉末浸渍法、溶液浸渍法三类制备聚乙烯单组分复合材料的传统方法。重点介绍了热压法、共挤出热压法两类制备单组分复合材料的创新方法。分析了各制备方法的优缺点:熔融法、粉末法与溶液法效率均较低且复合材料中纤维含量较少,力学性能不佳;热压法由于初始材料为100％纤维,从而综合效率较高,力学性能良好,缺点为加工温度过于苛刻;共挤出热压法效率较高,在具有高的增强相含量的同时拥有较宽的加工温度范围,缺点为增强相强度需进一步提高。最后介绍了单组分复合材料的应用并对其研究与应用前景作了展望。     

PP-R管材料熔融挤出过程MFR控制研究

分析了PP-R（无规共聚聚丙烯）管材料MFR（熔体流动速率）的变化对力学性能的影响，着重通过双螺杆挤出机研究了PP—R管材料熔融挤出过程中影响MFR变化的因素。结果表明，合适的加工工艺控制和优良的抗氧体系是保证PP-R管材料加工过程中MFR稳定的前提。     

High molecular weight polypropylene nanospheres: Synthesis and characterization

The high molecular weight (MW) polypropylene with average particle size of 60 nm was synthesized by controlled growth mechanism using Ziegler–Natta catalyst. The atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies showed that PP nanoparticles were spherical in shape. Structure and crystallinity were concomitantly studied through Fourier transform infrared spectroscopy and X‐ray diffraction, respectively. It shows nanospherical PP particles with more crystallinity (～ 75%) compared with macrosized PP (～ 59%). In addition, differential scanning calorimetry studies revealed the finite particle size effect on T_g and the scale dependence T_g followed a first order exponential trend. As particle size goes down to nano‐ scale from macrosize, continuous elevation of T_g's were observed from ?25 to ?11°C. This phenomenon was directed to configuration entropy of single spherical nanoparticles of PP. The mechanical properties and surface roughness were also evaluated through AFM. At last, the properties of nanosized PP were compared with micron and macrosized particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

油酸修饰纳米CaCO3对PP结晶行为和力学性能的影响

Oleic acid (OA)-modified CaCO3 nanoparticles were prepared using surface modification method. Infrared spectroscopy (IR) was used to investigate the structure of the modified CaCO3 nanoparticles, and the result showed that OA attached to the surface of CaCO3 nanoparticles with the ionic bond. Effect of OA concentration on the dispersion stability of CaCO3 in heptane was also studied, and the result indicated that modified CaCO3 nanoparticles dispersed in heptane more stably than unmodified ones. The optimal proportion of OA to CaCO3 was established. The effect of modified CaCO3 nanoparticles on crystallization behavior of polypropylene (PP) was studied by means of DSC. It was found that CaCO3 significantly increased the crystallization temperature, crystal-lization degree and crystallization rate of PP, and the addition of modified CaCO3 nanoparticles can lead to the for-mation of β-crystal PP. Effect of the modified CaCO3 content on mechanical properties of PP/CaCO3 nanocompo-sites was also studied. The results showed that the modified CaCO3 can effectively improve the mechanical proper-ties of PP. In comparison with PP, the impact strength of PP/CaCO3 nanocomposites increased by about 65% and the flexural strength increased by about 20%.     

Rubber‐toughened polypropylene nanocomposite: Effect of polyethylene octene copolymer on mechanical properties and phase morphology

Rubber‐toughened polypropylene (PP)/org‐Montmorillonite (org‐MMT) nanocomposite with polyethylene octene (POE) copolymer were compounded in a twin‐screw extruder at 230°C and injection‐molded. The POE used had 25 wt % 1‐octene content and the weight fraction of POE in the blend was varied in the range of 0–20 wt %. X‐ray diffraction analysis (XRD) revealed that an intercalation org‐MMT silicate layer structure was formed in rubber‐toughened polypropylene nanocomposites (RTPPNC). Izod impact measurements indicated that the addition of POE led to a significant improvement in the impact strength of the RTPPNC, from 6.2 kJ/m² in untoughened PP nanocomposites to 17.8 kJ/m² in RTPPNC containing 20 wt % POE. This shows that the POE elastomer was very effective in converting brittle PP nanocomposites into tough nanocomposites. However, the Young's modulus, tensile strength, flexural modulus, and flexural strength of the blends decreased with respect to the PP nanocomposites, as the weight fraction of POE was increased to 20 wt %. Scanning electron microscopy (SEM) was used for the investigation of the phase morphology and rubber particles size. SEM study revealed a two‐phase morphology where POE, as droplets was dispersed finely and uniformly in the PP matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3441–3450, 2006