N-羟甲基丙烯酰胺熔融接枝PP的流变性能

采用熔融接枝法在双螺杆挤出机上制得接枝率为0．20％～0．85％的N-羟甲基丙烯酰胺接枝聚丙烯(PP-g-NHA),讨论了接枝物的组成、剪切应力和剪切速率以及温度对PP-g-NHA熔体流变行为、熔体黏度的影响,测定了接枝物的非牛顿指数。在相同剪切应力时,PP-g-NHA的剪切黏度比PP低,但黏流活化能比PP高。     

羟甲基丙烯酰胺熔融接枝聚丙烯亲水性的研究

分别以羟甲基丙烯酰胺（NHA）、苯乙烯（St）为接枝单体,过氧化二异丙苯（DCP）为引发剂,用双螺杆挤出机制备了聚丙烯（PP）的接枝共聚物PP-g-NHA和PP-g-NHA/St。红外分析表明,NHA和St接枝到PP链上形成接枝共聚物。探讨了NHA用量、St用量、DCP用量及加工温度、螺杆转速对接枝率及接触角的影响。结果表明,NHA的最佳用量是3 %,此时接枝率达到最大值为1.6 %,接触角最小为83 °;随着DCP用量的增加,接枝率先增大后下降;加工温度不能太高,螺杆转速一定要大于40 r/min。     

聚丙烯熔融接枝丙烯酰胺甲基丙烷磺酸的研究

本文采用熔融接枝方法制备了聚丙烯接枝丙烯酰胺甲基丙烷磺酸共聚物，用光电子能谱，热分析仪器及红外光谱法对接枝物进行了定性定量表征，研究了单体，引发剂，螺杆转速及反应温度对接枝率和接枝效率的影响。     

N-羟甲基丙烯酰胺对硅丙乳液及乳胶膜性能的影响

将N-羟甲基丙烯酰胺(NMA)、端乙烯基聚硅氧烷大单体与丙烯酸酯类单体进行乳液共聚合反应,制备了稳定的自交联型的硅丙乳液。通过聚合过程的动力学,聚合稳定性,乳胶粒的粒径大小和分布,以及乳胶膜的耐水性和力学性能测试,结合乳胶粒的微观形态和胶膜的红外光谱和DSC分析,讨论了NMA的引入及聚合方法对硅丙乳液和乳胶膜性能的影响。结果表明,在NMA适量加入的情况下,聚合反应速度加快,聚合稳定性提高,乳胶膜的耐水性增强,并使乳胶膜的力学性能也得到较大的提高。     

聚丙烯固相接枝N—烃甲基丙烯酰胺（HMA）：1.微观结构的研究

本文介绍采用固相接枝方法合成 的聚丙烯／Ｎ－羟甲基丙烯酰胺接枝共聚物,通过约外光谱等测试手段对接枝物微观结构进行表征。     

聚丙烯固相接枝N—羟甲基丙烯酰胺（HMA）：2.PP—g—N—HMA／PVC合金的研究

本文采用固相接枝方法制备聚丙烯接枝Ｎ－羟甲基丙烯酰胺共聚物,并与ＰＶＣ进行共混,详细考察了合金的力学性能,加热稳定性及微观形态结构的变化。     

N-羟甲基丙烯酰胺含量的测定

<正> 由丙烯酰胺与甲醛合成的N-羟甲基丙烯酰胺(CH_?CHCONHCH_2OH)作为一种理想的交联剂广泛地应用于纺织、塑料、皮革、涂料等工业部门。通常用蒸氮法测定总氮量以确定其含量,由于样品中含有微量的丙烯酰胺,往往使结果偏高。本文采用次碘酸盐氧化-碘量法,获得满意结果。 1.方法原理碘在氢氧化钠溶液中生成次碘酸钠,它既能氧化样品中的游离甲醛,又能氧化N-羟     

PMR内标绝对测定法检测N-羟甲基丙烯酰胺的含量

介绍了 PMR内标绝对测定法测定 N-羟甲基丙烯酰胺的含量的新方法 ,在 δ4和 δ9处有 N-羟甲基丙烯酰胺的 PMR吸收峰 ,而在 δ7附近却没有吸收峰 ,所以可以用苯作为内标物 (其吸收峰在 δ7.3) ,同时丙酮作为溶剂 (它的所有的吸收峰都小于 δ4 ,不能检测出来 ) ,这样就选择 CH2 OH 的吸收峰进行测定。溶剂峰、杂质峰和 N-羟甲基丙烯酰胺以外的其它峰不会干扰内标物苯和 CH2 OH 的吸收峰。作者以作了方法的精确度测定 ,结果满意 ,同时也讨论了该方法的有关问题     

聚丙烯熔融接枝丙烯酰胺的研究

本文采用熔融接枝方法制备了聚丙烯接枝丙烯酰胺共聚物，用光电子能谱、广角ｘ－射线衍射、红外光谱方法对接枝物进行了定性，定量表征，讨论了单体和引发剂浓度对接枝率的影响，比较了接枝前后聚合物结晶形态的变化。     

甲基丙烯酸甲酯/羟甲基丙烯酰胺无皂乳液共聚合的研究

以甲基丙烯酸甲酯为主单体、N-羟甲基丙烯酰胺为功能性单体、K2 S2 O8为引发剂进行了无皂乳液共聚合的研究 ;探讨了固含量、单体配比、反应温度、引发剂含量等对乳液稳定性和粒径大小的影响 ,制备了固含量较高 ( 30 %)、稳定性较好的丙烯酸酯无皂乳液。研究结果表明甲基丙烯酸甲酯 /N-羟甲基丙烯酰胺无皂共聚合的最佳条件为固含量 30 %、功能性单体 2 0 %、引发剂 1 %、反应温度 75℃。     

丙烯酸丁酯与N-羟甲基丙烯酰胺共聚物增韧PLA

将丙烯酸丁酯(BA)与N-羟甲基丙烯酰胺(NA)共聚合制备柔性共聚物P(BA-NA),再用P(BA-NA)增韧聚乳酸(PLA),研究了增韧体系的力学性能、微观形态与共聚单体配比、共聚物含量之间的关系。当n(BA)/n(NA)为30∶1,w[P(BA-NA)]为8%时,PLA/P(BA-NA)复合材料的拉伸断裂应变提高了约97倍,悬臂梁缺口冲击强度提高了1.5倍,拉伸强度为39 MPa。采用扫描电子显微镜观察发现,P(BA-NA)能够均匀分散在PLA基体中,两者相容良好。     

Preparation and Application of Deformable and Orientable Intumescent Flame Retardants Incorporated with Polypropylene

An environment-friendly and easily operational method, reactive extrusion was adopted to prepare intumescent flame retardant (IFR), melamine salt of pentaerythritol phosphate (MPP) with special rheological properties. The outstanding advantage of the extruded MPP is that the flame retardant can deform, orientate and form fibrillar morphology in resin matrix during the incorporation with PP, however, conventional MPP can only solid-state disperse in PP melt phase and obtain granulated morphology. The deformation and orientation mechanism of the extruded MPP were researched by scanning electron microscope (SEM) and differential scanning calorimeter (DSC). It proved that this fibrillar morphology of the flame retardant obviously improved the flame retardancy and mechanical performance of PP.     

Effects of Magnesium Hydroxide Containing Copper Compound on the Properties of Polypropylene Composites

Rod-like morphological magnesium hydroxide nanoparticles were synthesized via coprecipitation with copper ions. Flame retardant composites were prepared by these particles and polypropylene. The microstructure, flame retardation, mechanical property, thermal oxidative degradation behavior and mechanism of these composites were discussed. The results demonstrated that these composites containing copper compound increased the flame retardation, but decreased the initial oxidative decomposition temperatures and mechanical properties. Thermogravimetric and infrared analysis showed that the decomposition procedure was divided into three stages. In addition, the degradation kinetics was analyzed by Flynn-Wall-Ozawa method, and it showed that polypropylene composites containing copper compound exhibited a different decomposition mechanism.     

Zn-Al-Ce-LDHs/PP复合材料的制备及性能研究

采用微波晶化低饱和态共沉淀法快速制备了层板上含有稀土铈元素的水滑石(LDHs),并将其应用于聚丙烯(PP)中通过熔融插层法制备了LDHs/PP复合材料。利用红外光谱、X射线衍射和透射电镜对LDHs进行了表征,并研究了LDHs/PP复合材料的阻燃性能和热降解性能。结果表明:当n(Zn2+)/n(Al3+)=3,n(Ce3+)/n(Al3+)=1/2时,所形成的Zn-Al-Ce-LDHs形貌最好,晶体结构最为规整;复合材料的阻燃性能随着Zn-Al-Ce-LDHs用量的增加而提高;当用量同为50%时,Zn-Al-Ce-LDHs/PP复合材料的氧指数达到28%,790℃下的残炭量为33.6%远,高于Mg-Al-LDHs/PP复合材料。     

阻燃聚丙烯的研究进展

基于聚丙烯的热分解机理,依照材料设计的思路,总结并概括出阻燃聚丙烯的开发已从最开始的单纯的配比添加向深层次的材料设计转变的研究方向。重点概括并论述了当前阻燃聚丙烯材料的开发设计思路,并举例分析了三种层面上的阻燃聚丙烯的国内外的研发进展及其不足。     

Recent Research Progress on the Flame-Retardant Mechanism of Halogen-Free Flame Retardant Polypropylene

Polypropylene (PP) is one of the five kinds of universal polymers that have greatly improved our life qualities. While a pestilent limitation of PP is its flammability. Usually, halogen-containing flame retardants (FRs) are used to improve its flame retard ability. However, the halogen-containing FRs are limited more and more strictly because they would produce environment problems, such as the release of corrosiveness smoke and toxicity combustion products. Hence, the researches of halogen-free FRs to replace the halogen-containing FRs become hot topics. In this article, the recent research progress of halogen-free FRs as additives for polypropylene and the flame retardant mechanism of halogen-free FRs are reviewed.     

Phase Morphology and Mechanical Properties of Rubber-Toughened Polypropylene Nanocomposites: Effect of Elastomer Polarity

The objective of this work was to investigate the effect of elastomer polarity on phase structure and mechanical properties of PP nanocomposites. The nonpolar and polar elastomers studied were polyethylene octene (POE) and polyethylene octene grafted maleic anhydride (POEgMAH), respectively. The results from mechanical studies showed that the POEgMAH-toughened polypropylene nanocomposites have higher Izod impact strength but lower tensile and flexural properties than the unmaleated ones. X-ray diffraction (XRD) was used to characterize the formation of nanocomposites. XRD studies revealed that intercalated rubber-toughened PP nanocomposites (RTPPNC) had been successfully prepared where the macromolecule segments PP were intercalated into the interlayer space of organoclay. XRD also indicated that the incorporation of polar POEgMAH elastomers into PP nanocomposites contribute to a better intercalation effect and formed a more exfoliated combinations structure compared to POE. Scanning electron microscope (SEM) was used for the investigation of the phase morphology and rubber particle size and particle-size distribution. SEM study revealed a two-phase morphology where POE as droplets dispersed finely and uniformly in the PP matrix. The POEgMAH-toughened PP nanocomposites shows a much finer dispersion of elastomer particles than POE-toughened PP nanocomposites.     

改性高岭土/聚丙烯复合材料的热性能及非等温结晶行为研究

以自制的剥离高岭(MK)、原高岭土(K)以及聚丙烯(PP)和马来酸酐接枝聚丙烯(PP-g-MA)等作为基本原料,通过熔融挤出、注塑成型,制备PP复合材料。采用XRD、DSC、TG研究复合材料的非等温结晶行为、结晶动力学以及热降解性能。结果表明:高岭土的加入,使结晶温度、结晶度、热稳定性都有所提高,且结晶速率加快,具有异相成核作用。与原高岭土相比,改性高岭土更能促进PP复合材料的PP异相成核,促进PP稳态晶型(α晶型)的转变,结晶速率较快。与纯PP和PP/PP-g-MA复合材料相比,PP/改性高岭土复合材料的结晶峰温度、最大热降解温度分别提高了16.7、7.8、9.7、12.6℃。     

Preparation and characterization of polypropylene/layered silicate nanocomposites using an antioxidant

Polypropylene (PP)/layered silicate nanocomposites were prepared via simple melt mixing of three components, PP, layered silicates modified with octadecylamine (C18-MMT) and antioxidant, to investigate the role of antioxidant. TEM and X-ray scattering results confirmed the intercalated state of silicates in PP/layered silicate nanocomposites with antioxidant. In rheological and mechanical study, the nanocomposites with antioxidant showed higher properties than those of the unfilled PP. The nanocomposite with 5 wt% C18-MMT and 0.5 phr antioxidant exhibited about 1.4 times higher tensile modulus and 1.3 times higher storage modulus than the unfilled PP. However, PP/C18-MMT without antioxidant showed lower rheological values owing to the thermal decomposition of PP and the poor compatibility between PP and C18-MMT. It could be concluded that antioxidants played an important role in enhancing the compatibility between PP and C18-MMT. According to the real time X-ray diffraction, the nanocomposite showed the weak ordering of PP crystals than the unfilled PP in the load-extension plateau region of elongation.