线型低密度聚乙烯固相接枝丙烯酸丁酯的研究

利用固相接枝共聚的方法,制备了线型低密度聚乙烯接枝丙烯酸丁酯(LLDPE-g-BA)共聚物。讨论了反应温度、反应时间、引发剂用量、单体浓度对接枝率的影响,结果表明:随着反应温度的升高,反应时间的延长,引发剂用量以及单体/聚合物比例的增加,接枝率提高,最高接枝率达到10.12%。并用红外光谱表征产物的结构。LLDPE-g-BA可明显改善PET/LLDPE复合材料的界面相容性及力学性能。     

线型低密度聚乙烯熔融接枝马来酸酐改性的初步研究

以马来酸酐为接枝单体在Ｂｒａｂｅｎｄｅｒ中驿ＬＬＤＰＥ进行了熔融接枝改性研究，了共共混温度、引发剂用量、单体用量以及混合时间对接枝过程的影响，并通过红外光谱证明了接枝反应的存在。     

线型低密度聚乙烯的改性研究进展

综述了近几年线型低密度聚乙烯(LLDPE)的改性在力学、阻燃、电学、结晶等性能上取得的研究进展,并对未来LLDPE改性的研究方向进行了展望。     

线型低密度聚乙烯抗静电母料的研究

研制了具有协同效应的复合抗静电剂配方,母料中抗静电剂含量为10%以上;使用该母料的专用料加工过程中不仅母料用量可减少,而且产品的加工工艺稳定;专用料的力学性能稳定。能使专用料表面电阻率(ρS)长短期都达到较低值的母粒用量为3.9%。     

线型低密度聚乙烯的分级制备北大核心

采用制备型升温淋洗分级仪对线型低密度聚乙烯(LLDPE)进行分级和收集,得到6个不同结晶度的级分,并利用差示扫描量热仪、傅里叶变换红外光谱仪、核磁共振波谱仪和凝胶渗透色谱仪分别对原样和级分的结晶熔融行为、短链支化度、相对分子质量及其分布进行了分析。结果表明:随着淋洗温度的升高,级分的结晶度增大、支化度降低、相对分子质量增大,且LLDPE试样中存在支化不均匀性,低相对分子质量部分聚乙烯的共聚单体含量较高,高相对分子质量部分聚乙烯的共聚单体含量较少。     

茂金属线型低密度聚乙烯共混性能的研究

研究了茂金属线型低密度聚乙烯(mLLDPE)、mLLDPE/低密度聚乙烯(LDPE)共混物的热性能、流变性能及薄膜样品的基本性能。热性能结果表明,在mLLDPE中添加LDPE使样品的结晶温度明显下降;毛细管流变试验结果表明,LDPE的添加使mLLDPE的剪切敏感性显著提高,利于其加工;薄膜样品性能研究结果表明,mLLDPE使得LDPE的力学性能明显提高,光学性能明显改善。     

影响低密度聚乙烯光接枝的因素

研究了空气气氛中以二苯甲酮为光敏剂时影响低密度聚乙烯（LDPE）光接枝的工艺因素。结果表明：随光照时间的延长、反应温度的升高、紫外光光强的增加，LDPE的有效接枝率增加；与丙烯酰胺单体相比，LDPE接枝丙烯酸的有效接枝率高，当单体浓度为2mol/L时，有效接枝率达极大值。光接枝LDPE对水的接触角随有效接枝率的增加而降低，当接枝率达一定值时，接触角不再随接枝率的变化而变化。     

线型低密度聚乙烯生产和工艺技术新进展

介绍了近年线型低密度聚乙烯生产、研究和应用领域的现状和发展前景,分析了国内对LLDPE供需概况、消费分布、进口情况和发展趋势。     

改性蛋白土填充线型低密度聚乙烯的研究

对超细加工并经硅烷偶联剂处理的蛋白土填充线型低密度聚乙烯进行了研究,结果表明:采用适当的偶联剂及恰当的添加量,改性蛋白土可以降低塑料的成本。     

线性低密度聚乙烯超微薄膜的加工和应用

介绍了线性低密度聚乙烯超微薄膜的加工技术和应用情况。     

马来酸酐-苯乙烯熔融接枝POE的研究

以过氧化二异丙苯（DCP）为引发剂,在双螺杆挤出机上实现了苯乙烯（st）协效马来酸酐（MAH）熔融接枝乙烯-辛烯共聚物（POE）;采用正交实验设计重点考察MAH、MAH/DCP及st/MAH含量对接枝率Gd（%）的影响。结果表明：MAH含量对Gd（%）的影响最为显著,其次是MAH/DCP,st/MAH的影响最小;MAH...     

聚丙烯蜡接枝丙烯酰胺的合成工艺研究

用熔融接枝方法制备了聚丙烯蜡接枝丙烯酰胺(PPW-g-AM),用红外光谱、化学滴定法对接枝物进行了定性和定量的表征,讨论了单体、引发剂、反应时间对接枝率和接枝效率的影响。结果表明:在100～110℃下,PPW用量为50g、AM用量为10g、BPO用量为2.0g,反应时间为2h时,可获得最佳的接枝率和接枝效率,并利用红外光谱证实了PPW-g-AM的存在。     

无卤阻燃线性低密度聚乙烯技术的研究进展

综述了近几年国内外线性低密度聚乙烯(LLDPE)阻燃体系的研究现状,包括磷系、硅系、无机氢氧化物、膨胀型以及近几年迅速发展的纳米级阻燃剂;分析了各类无卤体系阻燃的机理以及研究进展。最后对LLDPE的阻燃前景进行展望,纳米级阻燃剂将是未来的研究热点。     

硅烷接枝LLDPE结晶结构的研究

用傅立叶变换红外光谱(FT-IR)、X射线粉末衍射仪(XRD)、差示扫描量热仪(DSC)分析了接枝率对硅烷接枝线型低密度聚乙烯(SGLLDPE)晶体结构和熔融行为的影响,并对晶体结构和熔融行为之间的关系进行了初步探索。结果表明:随着接枝率增加,晶面间距基本不变,晶粒尺寸逐渐减小;接枝后熔点降低且低温熔融峰热流量逐渐增大,高温熔融峰热流量逐渐减小。     

Grafting of methyl methacrylate (MMA) onto Antheraea assama silk fiber

Graft copolymerization of methyl methacrylate (MMA) onto nonmulberry silk fiber Antheraea assama was investigated in aqueous medium using the KMnO₄–oxalic acid redox system. Grafting (%) was determined as a function of the reaction time, temperature, and monomer and initiator concentrations. The rate of grafting increased progressively with increase of the reaction time up to 4 h and then decreased. The extent of grafting was maximum at 55°C. The extent was also dependent upon monomer and initiator concentrations up to 75.5 × 10^?2 and 6 × 10^?3 M, respectively. The grafted products were evaluated by infrared spectroscopy and their thermal decompositions were studied by TG and DTG techniques in static air at 20°C min^?1 and 30°C min^?1 in the range 30–800°C. The kinetic parameters for ungrafted and grafted fibers were evaluated using the Coats and Redfern method. The grafted products were found to be thermally more stable than were those of the ungrafted fibers. The surface characteristics of the ungrafted and grafted fibers were evaluated by scanning electron microscopy. The water‐retention values (WRVs) of the grafted fibers were in decreasing order with increase in the grafting (%). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2633–2641, 2001     

国内线性低密度聚乙烯现状

综述了国内线性低密度聚乙烯市场应用、生产情况、消费状况及技术进展情况,并提出了以后的发展建议。     

Preparation and Properties of a Reactive Type Nonionic Surfactant Grafted Linear Low Density Polyethylene

Summary A reactive type nonionic surfactant, monostearic acid monomaleic acid glycerol diester (MMGD) was synthesized in our laboratory. Grafting-copolymerization of linear low density polyethylene (LLDPE) with MMGD was carried out by using β ray irradiation in air in a twin-screw extruder. Evidence of the grafting of MMGD as well as its extent was determined by Fourier-transformed infrared (FT-IR) spectroscopy. The effects of monomer concentration, reaction temperature and screw run speed on degree of grafting were studied systematically. The thermal behavior of LLDPE-g-MMGD was investigated by using differential scanning calorimety (DSC). Compared with neat LLDPE, the crystallization temperature (T_c) of LLDPE-g-MMGD increased about 3 °C, and the melting enthalpy (ΔH_m) decreased with increase of MMGD content. It showed that the grafted MMGD monomer onto LLDPE acted as a nucleating agent. The tensile properties and light transmission of blown films were determined. Comparing with neat LLDPE film, no obvious changes could be found for the tensile strength, elongation at break and right angle tearing strength of LLDPE-g-MMGD film. The wettability is expressed by the water contact angle. With an increasing percentage of MMGD, the contact angles of water on film surface of LLDPE-g-MMGD decrease monotonically. Accelerated dripping property of film samples was investigated. The dripping duration of LLDPE-g-MMGD film and commercial antifog dripping film at 60 °C were 52 days and 17 days, respectively.     

Synthesis and Characterization of Linear Low Density Polyethylene Grafted Glycerol Monolauric Acid Monoitaconic Acid Diester

A reactive type dripping agent, glycerol monolauric acid monoitaconic acid diester (GLID) was synthesized in our laboratory. Grafting-copolymerization of linear low density polyethylene (LLDPE) with GLID was carried out by using β-ray irradiation in air in a twin-screw extruder. FT-IR was used to characterize the formation of grafting copolymer and evaluate their degree of grafting. The effects of monomer concentration, reaction temperature and screw run speed on degree of grafting were studied systematically. Crystallization rates of grafted LLDPE were faster than that of plain LLDPE at a given crystallization temperature. The tensile properties and light transmission of blown films were determined. Comparing with neat LLDPE film, no obvious changes could be found for the tensile strength, elongation at break and right angle tearing strength of LLDPE-g-GLID film. Acceleration dripping property of film samples was investigated. The dripping duration of LLDPE-g-GLID film and commercial antifog dripping film at 60° C were 69 days and 17 days, respectively.     

Grafting of partially hydrolysed poly(methyl methacrylate) onto mesylated cellulose acetate

A new synthetic route to cellulose graft polymers by nucleophilic displacement of mesylate groups from mesyl cellulose acetate (MCA) by the polystyrylcarboxylate anion has been recently reported by us. This approach to cellulosic graft polymers overcomes the drawbacks of the radical polymerization methods and allows for precise control of parameters such as the molecular weight and molecular weight distribution of the grafted side chains, higher degree of substitution on the cellulose backbone, the number and nature of grafted side chains and overall better control and reproducibility of the grafting process. In this report, partially hydrolysed poly(methyl methacrylate) was successfully grafted on to mesylated cellulose acetate in excellent yields by nucleophilic displacement of mesylate groups in less than 60 min at 75°C.