硅烷接枝ABS树脂及其水解交联的研究

在Haake密炼机中进行硅烷和ABS树脂的接枝反应,接枝产物在沸水中进行水解交联。研究了硅烷种类和用量、引发剂种类和用量对接枝率和凝胶率的影响,同时考察了反应条件对凝胶率的影响。结果表明,在本研究范围内,对于ABS树脂,只有使用3－甲基丙烯酰氧基三甲氧基硅烷（VMMS）作为接枝单体和丙烯酰胺作为引发剂才能得到一定的凝胶率。接枝率随单体用量增加而增加,凝胶率则先升高后趋于一定值。接枝率和疑胶率还随引发剂用量的增加先迅速增加后趋于一定值。温度和转速较低时,对凝胶率没有明显影响,但温度和转速很高时,凝胶率有所下降。     

硅烷接枝温水交联天然橡胶的研究

以多功能乙烯基硅烷为接枝单体,过氧化苯甲酰为引发剂,通过熔融混炼接枝和温水交联分别制备了硅烷接枝天然橡胶和交联硅烷接枝天然橡胶。采用傅里叶红外光谱仪和扫描电子显微镜分别对硅烷接枝天然橡胶和交联硅烷接枝天然橡胶进行了表征,并研究了接枝单体及引发剂的用量、接枝和交联工艺（温度和时间）等对交联硅烷接枝天然橡胶凝胶含量的影响,同时研究了不同凝胶含量对交联硅烷接枝天然橡胶力学性能的影响。结果表明,天然橡胶发生了硅烷接枝和交联反应;随着接枝单体及引发剂用量、混炼时间和温度以及交联温度和时间的增加,交联硅烷接枝天然橡胶的凝胶含量单调增加;交联硅烷接枝天然橡胶的力学性能随着凝胶含量的增加而明显得到改善,凝胶含量为80%的交联硅烷接枝天然橡胶的拉伸强度比纯天然橡胶提高了30%,断裂伸长率提高了8.5倍。     

乙烯-醋酸乙烯共聚物的硅烷交联及无卤阻燃研究

采用过氧化物为引发剂,用熔融法制备了硅烷交联EVA和无卤阻燃硅烷交联EVA.用红外方法(IR)和差示扫描量热法(DSC)对EVA的硅烷接枝反应进行了表征.研究了过氧化物含量对体系凝胶含量,相对接枝率和力学性能的影响,同时还研究了交联对体系阻燃性能的影响.DSC实验表明,硅烷A171比硅烷A151更容易接枝到EVA上.随DCP含量增加,体系的凝胶含量,相对接枝率,拉伸强度增加,而断裂仲长率降低.氧指数结果表明,交联以后可以适当提高氧指数值,改善阻燃性能.     

硅烷接枝和交联工艺对天然橡胶性能的影响

以六接剂三甲氧基硅烷为接枝单体、过氧化苯甲酰为引发剂,采用熔炼加温水交联方法制备硅烷接枝天然橡胶(NR),研究引发剂和硅烷用量、接枝和交联工艺对硅烷接枝NR溶胀比的影响以及凝胶含量对硅烷接枝NR性能的影响。结果表明:硅烷接枝NR的溶胀比随着引发剂和硅烷用量增大、交联温度提高、交联时间延长和试样厚度增大而增大,随着混炼时间延长和混炼温度提高呈先减小后增大的趋势;随着凝胶含量的增大,硅烷接枝NR的邵尔A型硬度增大,热稳定性改善。     

聚丙烯硅烷接枝水解交联

上海交通大学的吕晖辉等采用过氧化物为引发剂在挤出机中进行硅烷和ＰＰ的接枝反应。研究了凝胶率和硅烷单体种类和用量、引发剂种类和用量、苯乙烯（Ｓｔ）用量之间的关系,亦研究了反应条件对凝胶率的影响。结果表明,凝胶率随单体浓度增加而增加。３甲基丙烯酰氧基丙基三甲氧基硅烷（ＶＭＭＳ）比乙烯基三乙氧基硅烷（ＶＴＥＳ）和乙烯基三甲氧基硅烷（ＶＴＭＳ）的接枝效果好;凝胶率还随引发剂用量的增加而增加,用ＢＰＯ比用ＤＣＰ得到的凝胶率高;随苯乙烯用量的增加凝胶率增加,但当Ｓｔ∶ＶＭＭＳ达１５∶１时,变化不大;反应温…     

聚丙烯硅烷接枝水解交联

采用过氧化物为引发剂在挤出机中进行硅烷和ＰＰ的接枝反应。研究了凝胶率和硅烷单体种类和用量、引发剂种类和用量、苯乙烯用量之间的关系,对反应条件对凝胶率的影响亦进行了研究。结果表明,凝胶率随单体浓度增加而增加。ＶＭＭＳ比ＶＴＥＳ和ＶＴＭＳ的接枝效果好;凝胶率还随引发剂用量的增加而增加,ＢＰＯ比用ＤＣＰ得到的凝胶率高;随苯乙烯用量的增加凝胶率增加,但当Ｓｔ∶ＶＭＭＳ达１５∶１时,变化不大;反应温度提高使凝胶率下降,转速增加使凝胶率增加     

不饱和硅烷熔融挤出接枝聚乙烯

上海交通大学高分子材料研究所的王文杰等采用熔融挤出法对低密度聚乙烯（ＰＥ）进行硅烷接枝,然后在催化剂二丁基二月桂酸锡存在下进行水解交联,接枝单体为乙烯基三乙氧基硅烷（ＶＴＥＳ）,主要引发剂为过氧化二异丙苯。研究了改变ＶＴＥＳ用量、引发剂种类与用量、ＰＥ种类、接枝反应条件、加入添加剂对接枝产物的融体流动速率（ＭＦＲ）和交联样品的凝胶率的影响。结果发现,在ＶＴＥＳ用量较低时,用量增加能够提高凝胶率和ＭＦＲ;但质量分数超过２％后凝胶率基本不再随硅氧烷用量增加而上升,而ＭＦＲ有明显降低。引发剂用量增大有…     

硅烷交联高密度聚乙烯的正交实验研究

研究了硅烷交联聚乙烯的整个反应过程,以HDPE、过氧化物和不饱和硅烷为基本原料,首先通过挤出熔融法将不饱和硅烷接枝到聚乙烯链上,然后将接枝物进行水解交联反应制得交联产品。通过实验研究了引发剂、硅烷、催化剂对拉伸强度的影响。在工艺条件得到优化的情况下,应用三因素四变量正交设计确定了最佳配方。引发剂、硅烷、催化剂的用量分别为 1phr、1.4phr、0.6phr。讨论了交联温度、交联时间对拉伸强度以及交联时间对凝胶率和维卡软化点的影响     

硅烷接枝交联聚烯烃共聚物POE的研究

以过氧化二异丙苯(DCP)作为引发剂,使用哈克(HAAKE)流变仪研究了乙烯基三乙氧基硅烷(VTES)接枝交联不同型号的聚烯烃弹性体(POE)(TAFMER DF610、Vistamaxx 6202、Koattro KT-MR-05)的反应规律。结果表明,VTES以化学键接枝到POE分子链上。加工过程中扭矩变化和接枝交联的反应程度与POE的种类有直接关系,其中,DF610更容易预交联,接枝率较高;而Vistamaxx 6202和KT-MR-05在反应过程中产生降解,接枝率较低。对产品凝胶含量影响因素进行方差分析表明,水解前对凝胶含量影响严重的是DCP的含量,而水解后硅烷含量的变化对凝胶含量影响显著。     

硅烷固相接枝熔融法制备交联聚丙烯

以硅烷为接枝单体，采用固相接枝法得到硅烷接枝聚丙烯，将接枝产物水解熔融得到交联聚丙烯（MPP），研究了接枝单体和引发剂种类对聚丙烯（PP）固相接枝率的影响，选择相同条件下接枝率最大时所用单体3-（甲基丙烯酰氧）丙基三甲氧基硅烷（MAPTMS）和引发剂过氧化苯甲酸叔丁酯（TBPB）考察后续交联产物性能，进一步研究了MAPTMS和TBPB加入量对MPP熔体流动速率（MFR）、凝胶含量、结晶温度、熔融温度、弹性模量和复数黏度的影响。结果表明：与纯PP相比，MPP的MFR降低，凝胶含量、弹性模量、复数黏度均升高，当MAPTMS与TBPB加入量分别为0.06,4.00 mL时，MPP的MFR降至2.4 g/10 min，凝胶含量高达54%，弹性模量和复数黏度均达到最大；与纯PP相比，MPP显示出更高的结晶温度，更低的结晶温度，产物不发生相分离。     

A few physical properties of grafted polyethylene and nylon films

Methyl methacrylate, vinyl acetate, or N-vinylpyrrolidone was graft-copolymerized onto low-density polyethylene or nylon 6 film by simultaneous irradiation method. Higher extent of grafting was attained by liquid-phase grafting than by vapor-phase grafting. The relative change in the degree of crystallinity of backbone polymer caused by grafting was measured with differential scanning calorimetry. In polyethylene-g-vinylpyrrolidone, the degree of crystallinity decreased markedly with the extent of grafting. However, in other grafted films, especially in grafted nylon, the crystallinity decrease was limited, or substantially no decrease was observed in a few systems. Water vapor permeability of the grafted films changed uniformly with increasing extent of grafting, and particularly polyethylene- and nylon-g-vinylpyrrolidone films showed excellent permeability, and some were able to be used as dialyzer. The difference in grafting method, liquid-phase grafting or vapor-phase grafting, produced no difference in those properties. The grafting was found to bring about a change in the molecular orientation of the original film.     

丙烯酸接枝聚丙烯的制备及其结构与性能

综述近年来国内外关于丙烯酸接枝聚丙烯(PP—g—AA)的制备方法,主要包括熔融接枝、固相接枝、辐射接枝、光引发接枝、悬浮接枝、溶液接枝和复合材料中的原位接枝法等,以及各种制备工艺和条件对接枝率的影响;并对PP—g—AA的结构与性能尤其是接枝丙烯酸后聚丙烯的结晶与熔融行为进行了详细阐述。     

聚丙烯固相接枝马来酸酐的研究

采用先降解后固相接枝技术,以马来酸酐（MAH）为单体,在自制的搅拌反应器中制备了马来酸酐接枝聚丙烯接枝物（PP-g-MAH）,并对其结构进行了表征与分析,研究了接枝反应时间、接枝反应温度、引发剂质量分数和单体质量分数对接枝率的影响。结果表明,接枝反应温度为120℃、引发剂质量分数为4%、单体质量分数为14%、接枝反应时间为2.5h时,可得到接枝率为2.85%的PP-g-MAH。     

辐射接枝法生产离子交换纤维的进展

介绍了辐射接枝生产离子交换纤维的主要方法 :共辐射接枝法、无氧预辐射接枝法和有氧预辐射接枝法。比较了这些方法的优缺点 ,指出有氧预辐射接枝更适合于工业化生产。对今后辐射接枝生产离子交换纤维的发展进行了展望     

CPP-g-MAH的制备及其接枝效率的影响因素

考察了反应温度、加料方式、反应时间、引发剂用量对马来酸酐接枝氯化聚丙烯接枝率和接枝效率的影响。通过改进接枝工艺,优化反应条件,提高了马来酸酐的接枝效率。在较低马来酸酐用量下制备出接枝率约2%、接枝效率达到80%左右的接枝产品,显著降低了原料消耗。     

Comparative study of the radiation‐induced grafting of styrene onto poly(tetrafluoroethylene‐co‐perfluoropropylvinyl ether) and polypropylene substrates. I: Kinetics and structural investigation

A comparative study has been made of the radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐perfluoropropyl vinyl ether) (PFA) and polypropylene (PP) substrates, using the simultaneous irradiation method. Effects of grafting conditions such as monomer concentrations, type of solvent, dose rate and irradiation dose on the grafting yield were investigated. Under the same grafting conditions it was found that a higher degree of grafting of styrene was obtained using a mixture of dichloromethane/methanol solvents for PFA and methanol for PP and the degree of grafting was higher in PP than in PFA at all doses. However, the micro‐Raman spectroscopy analysis of the graft revealed that, for the same degree of grafting, the penetration depth of the grafted polystyrene into the substrate was higher in PFA than in PP substrates. In both polymers the crystallinity was hardly affected by the grafting process and the degree of crystallinity decreased slightly with grafting dose. The dependence of the initial rate of grafting on the dose rate and the monomer concentration was found to be 0.6 and 1.4 order for PFA and 0.15 and 2.2 for PP, respectively. The degree of grafting increased with increasing radiation dose in both polymers. However, the grafting yield decreased with an increase in the dose rate. The increase in the overall grafting yield for PFA and PP was accompanied by a proportional increase in the penetration depth of the graft into the substrates. Copyright © 2003 Society of Chemical Industry     

Modification of polypropylene fiber by radiation-induced graft copolymerization of acrylonitrile monomer

Modification of polypropylene fiber was carried out by graft copolymerization of acrylonitrile monomer using the preirradiation method. The influence of synthesis conditions (preirradiation dose, monomer concentration, temperature, draw ratio, and storage) on the degree of grafting was investigated. For all preirradiation doses, the degree of grafting was found to increase with the reaction time. The higher the preirradiation dose, the higher the degree of grafting was. The dilution of monomer with DMF showed peak maxima for the degree of grafting at 80% monomer concentration. Both the initial rate of grafting and the final degree of grafting were found to increase with an increase in the reaction temperature. An activation energy of 31.2 kJ/mol was found for the grafting reaction. The degree of grafting in the drawn fiber showed different behavior as compared to the undrawn fiber. The storage of the irradiated fiber at −4°C prior to the grafting showed a decrease in the degree of grafting initially for a period of 8 days, beyond which the degree of grafting remained constant. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1343–1348, 1998     

The study on radiation grafting of acrylic acid onto fluorine-containing polymers. III. Kinetic study of preirradiation grafting onto poly(tetrafluoroethylene–hexafluoropropylene)

A kinetic study has been made on the preirradiation grafting of acrylic acid (AAc) onto poly(tetrafluoroethylene–hexafluoropropylene) (FEP) film. The effect of grafting conditions was investigated. The dependencies of the grafting rate on preirradiation dose and monomer concentration were found to be 0.58 and 1.25 order, respectively. The overall activation energy for the graft polymerization was 7.4 kcal/mol. The final degree of grafting increased with preirradiation dose and monomer concentration and slightly decreased as the grafting temperature was elevated. The relationship between the grafting rate and film thickness gave a negative first-order dependency, which is in agreement with that obtained for polytetrafluoroethylene—AAc grafting system. It was reasonably concluded that this grafting proceeds from the surface to the center of film with progressive monomer diffusion through the grafted layer which swells in the monomer solution.     

Grafting of methyl methacrylate onto collagen initiated by tributylborane

The graft copolymerization of methyl methacrylate onto collagen initiated by tributylborane was investigated in aqueous medium. The total conversion, percentage of grafting and efficiency of grafting increased with increasing collagen content. The optimum conditions on the percentage of grafting and efficiency of grafting were determined by varying initiator concentration, monomer concentration, and polymerization temperature. The grafting onto denaturated collagen was also studied. It has been suggested that the grafting onto collagen proceeds by a radical mechanism via a complex of TBB and hydrated collagen.     

醋酸乙烯酯乳液与聚乙烯醇接枝反应的研究

研究了以聚乙烯醇为保护胶体的醋酸乙烯乳液聚合中,作为保护胶体的聚乙烯醇与醋酸乙烯的接枝反应。发现聚乙烯醇的接枝主要发生在初期,而醋酸乙烯的接枝链一直增长到胶粒沉析;另外,保护胶体黏度对接枝率也有影响,黏度越大醋酸乙烯的接枝率越低。