共查询到18条相似文献,搜索用时 265 毫秒
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超临界CO2协助固相接枝改性PP研究进展 总被引:1,自引:0,他引:1
聚丙烯(PP)接枝改性方法很多,其中超临界CO2协助固相接枝法是一种高效节能的方法。系统地比较了各种接枝方法,综述了超临界CO2协助固相接枝聚丙烯时超临界流体的优点和作用,介绍了超临界CO2溶胀聚丙烯过程各参数的影响,同时对聚丙烯固相接枝反应的影响因素进行了论述,并简单概括了接枝产物的各种表征手段及应用。 相似文献
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丙烯酸固相接枝聚丙烯反应规律性研究 总被引:8,自引:0,他引:8
通过正交试验及其单因素实验深入地研究了丙烯酸固相接枝聚丙烯反应的规律,考查了影响固相接枝反应的动力学因素和非动力学因素,并研究了以苯乙烯为共单体的固相接枝反应规律。 相似文献
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聚丙烯固相法接枝改性 总被引:3,自引:0,他引:3
聚丙烯固相法接枝不饱和单体是一种简便易行的本体法技术。与其它接枝方法相比,具有成本低、接枝率高、时间短、无溶剂回收、不妨害接枝物的进一步应用等优点。本文介绍了聚丙烯固相法接枝不饱和单体的进展,并较详细地讨论了影响接枝反应的各种因素。 相似文献
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聚丙烯无纺布预辐射固相接枝丙烯酸的研究 总被引:1,自引:0,他引:1
以聚丙烯(PP)无纺布为基材,以丙烯酸为单体,进行预辐射固相接枝聚合,考察了外部环境、辐射剂量、温度、反应时间、单体用量、介质、阻聚剂、交联剂对接枝率的影响。结果表明,通过预辐射固相接枝聚合方法,可将丙烯酸单体接枝在PP无纺布上,辐射剂量增大可提高接枝率;反应时间对接枝率的影响在低、高温阶段有所不同。最佳反应条件为:氮气环境,辐射剂量大于50 kGy,反应温度65℃,反应时间3 h,单体浓度30%,反应介质为水,阻聚剂0.8 g,交联剂用量为5 mL。 相似文献
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固相接枝共聚法制备PP—g—PS 总被引:4,自引:0,他引:4
用固相接枝共聚方法制备了聚丙烯接枝苯乙烯(PP-g-PS),详细地考察了聚丙烯与引发剂的品种、反应温度、苯乙烯及引发剂的浓度等因素对接枝率和接枝效率的影响。研究结果表明:PP-g-PS具有较高的接技率,应用于聚丙烯/聚苯乙烯(PP/PS)共混物中,能降低分散相PS的粒径,提高PP/PS的相容性。 相似文献
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利用固相接枝技术,在自由基引发剂存在下,用2种不同熔体流动速率(MFR)的线型低密度聚乙烯(LLDPE)制备了马来酸酐接枝物(LLDPE-g-MA),研究了工艺条件对产物接枝率(DG)和凝胶含量(DC)的影响,结果表明,在相同工艺条件下,反应6 h后,接枝率都保持在2%以上,但低MFR的LLDPE原料,在接枝反应过程中容易发生交联,产品的凝胶含量接近60%,而用高MFR的LLDPE原料得到的产品凝胶含量低于2%。同时用IR、DSC和X衍射表征了产物的结构,结果表明,MA接枝主要发生在PE的非晶区,对PE的结晶结构没有很大影响。 相似文献
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γ辐射硅橡胶固相接枝甲基丙烯酸甲酯的研究 总被引:2,自引:0,他引:2
利用60Coγ射线,研究了硅橡胶(SR)与甲基丙烯酸甲酯(MMA)固相接枝反应,考察了接枝单体浓度、辐射剂量和剂量率等因素对接枝反应的影响,用红外光谱(FT-IR)、热重分析(TG)、和接触角测定仪等分析手段对接枝产物的结构和性能进行了表征分析。实验结果表明:辐射剂量和单体浓度分别为30kGy和m(MMA)/m(SR)=0.1左右时,接枝效果较好,接枝后的硅橡胶的热性能和亲水性能得到改善。 相似文献
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Grafting of vinyl monomers onto isotactic polypropylene (iPP) in the solid state, that is, below the melting point, displays several advantages over melt or solution grafting processes, such as negligible degradation of the iPP and absence of any solvent. The final properties of such iPP modifications or actually compatibilized PP blends are dependent on the dispersion of the new polymer into the iPP matrix, which is controlled to a large extent by the degree of grafting versus the amount of free homopolymer formed. In the present work, the solid‐state modification of iPP by styrene has been investigated from the point of view of the monomer polymerization behavior. In order to determine the styrene conversion and the distribution of the newly formed PS phase along the radius of the iPP powder particles, the reaction products were characterized by infrared (FTIR) and Raman spectroscopy. Fractionation of the reaction products via selective solvent extraction allowed the determination of the grafting efficiency (Φ). It was shown that besides the grafted PS two additional types of PS are formed, that is, free PS homopolymer in the pores of the PP powder and free PS in the amorphous PP phase. Phi shows an optimum as a function of the feed peroxide composition and the feeding rate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3279–3291, 2003 相似文献
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Nanocomposites of polypropylene (PP) and montmorillonites (MMT) were prepared by solid‐phase grafting reactive organomontmorillonite (ROMT) and polar monomers onto powdered PP and melt‐blending granule PP with the master batches as PP/MMT grafting copolymers (PPMG). The structure and properties of the PP/MMT nanocomposites (PPMN) were investigated by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD) patterns, transmission electron microscopy (TEM), dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric analysis. GPC showed that the numerical molecular weight and polydispersity of the graft copolymers of PPMG were approximately 4793 and 2.197, respectively. FTIR confirmed the solid‐phase graft copolymerization. XRD and TEM indicated the formation of the exfoliated, layered silicates (tactoids). The mole ratio of compound alkylammoniums and the exothermic enthalpy from solid‐phase graft copolymerization played key roles in the formation of tactoids. The optimum mole ratio of organophilic alkylammonium to reactive alkylammonium was 3 : 1. The mechanical and thermal properties increased with the contents of PPMG, and a preferable state was achieved at approximately 8 phr PPMG (parts of reagent per 100 parts of PP) because of the plastification of the exfoliated silicates and the graft copolymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3889–3899, 2006 相似文献
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聚丙烯固相接枝丙烯酸聚合动力学及其接枝聚合速率模型 总被引:12,自引:4,他引:8
基于自由基固相接枝聚合的终止反应主要是自由基单基终止反应的假设提出了相应的聚合机理,并建立了聚合速率模型,聚合速率与引发剂浓度呈1次方、与单体浓度呈小于1次方关系,与聚合温度服从Arrhenius关系.实验考察了聚丙烯固相接枝丙烯酸体系聚合温度、引发剂浓度、单体浓度与初始接枝聚合速率的依赖关系,这一关系与上述速率模型十分吻合.采用无约束非线性优化方法得到了各参数的全局最优解:频率因子为6.868×109,表观活化能为58.89 kJ8226;mol-1,单体浓度的幂为0.78. 相似文献