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1.
马来酸酐溶液法接枝无规聚丙烯的研究   总被引:10,自引:0,他引:10  
采用溶液法选用极性单体马来酸酐,在非隔氧条件下,对无规聚丙烯进行接枝改性。考察了不同温度、引发剂浓度、反应时间等因素对产物接枝率的影响,并用正交法指出影响因素的显著性,确定了控制MAPP接枝率的主要参数,找出了合成马来酸酐接枝无规聚丙烯(MAPP)的方法、体系与条件。采用红外及化学滴定等方法对聚合物的接枝率和结构进行了表征,证实了实验结果及相关理论的解释。  相似文献   

2.
温亦兴 《广州化学》2013,38(2):77-82
马来酸酐(MAH)是聚丙烯改性中最常用的极性单体,在连续反应中酸酐基呈现很高的活性,反应产物热稳定性良好,可被应用于合金,塑料等材料的生产。随着各种技术的广泛应用,马来酸酐接枝聚丙烯改性方法得到了快速的发展。各种马来酸酐接枝聚丙烯的改性方法有:溶液接枝法、熔融接枝法、固相接枝法和辐射接枝法。文章阐述了马来酸酐接枝聚丙烯改性方法的研究现状及其产物在不同领域的应用。  相似文献   

3.
马来酸酐与聚烯烃接枝产物的表征   总被引:22,自引:1,他引:21  
综述了马来酸酐与聚烯烃接枝产物的多种表征手段,重点分析了纯化处理,化学滴定以及红外分析方法的表征原理,应用和改进方法。  相似文献   

4.
马来酸酐接枝聚丙烯的等温结晶动力学研究   总被引:17,自引:2,他引:15  
用DSC法追踪了马来酸酐接枝聚丙烯的等温结晶过程,讨论了马来酸酐降低聚丙烯球晶径向生长自由能,提高结晶速率,但降低聚丙烯结晶度的物理和化学机制.同时探讨了马来酸酐的接枝对球晶生长和成核机制的影响.  相似文献   

5.
聚丙烯—马来酸酐接枝共聚物的固态NMR谱研究   总被引:1,自引:0,他引:1  
马来酸酐接枝聚丙烯的方法曾有过研究,但主要是熔融法和溶液法,反应温度在160℃以上,得到PP—g—MA共聚物。Russeli等曾对马来酸酐接枝二十烷烃作模型化合物进行过研究,~(13)C—NMR谱的结果表明在正二十烷烃主链上形成的主要为单马来酸环支链,未发现形成长链的马来酸酐均聚物,其原因为反应温度已超过马来酸酐聚合的最高温度(150℃)。  相似文献   

6.
聚丙烯与马来酸酐和苯乙烯在超临界CO2中的双组分接枝   总被引:15,自引:0,他引:15  
聚丙烯与马来酸酐和苯乙烯在超临界CO2中的双组分接枝  相似文献   

7.
添加型聚丙烯大分子表面改性剂PP-g-PEG的制备及其应用   总被引:3,自引:0,他引:3  
以马来酸酐为桥联剂,通过其与单端羟基聚乙二醇的反应,合成了大分子表面改性剂聚丙烯-聚乙二醇接枝共聚物,探索了反应条件对接枝反应的影响,用IR、NMR、TGA、DSC对接枝物的结构及性能进行研究,并通过共混研究了接枝物对聚丙烯的表面改性效果.结果表明,提高马来酸酐接枝聚丙烯或聚乙二醇的分子量,会阻碍接枝反应的进行,接枝率明显下降;接枝聚乙二醇降低了接枝物的结晶能力;聚丙烯-聚乙二醇接枝共聚物的热稳定性随着聚乙二醇的含量增加及侧链聚乙二醇长度的增加略有下降;聚丙烯-聚乙二醇接枝共聚物组分在共混物中具有明显的向外择优迁移特性,可以作为聚丙烯的添加型表面改性剂使用.  相似文献   

8.
制备了高抗冲聚苯乙烯和马来酸酐的接枝共聚物,利用红外光谱,电子能谱和动态力学谱对产物的结构进行了表征,并通过滴定法测定了接枝物中马来酸酐的含量。结果表明马来酸酐接技到了高抗冲聚苯乙烯中顺丁橡胶的分子链上,接技率为4.7%。研究了该接枝共聚物对PA1010/HIPS共混物的增容作用。电镜照片显示,随着共聚物中接枝物含量的增加,分散相相区尺寸明显减小,说明增容效果显著。测定了共混体系的拉伸行为,研究了  相似文献   

9.
溶液法马来酸酐接枝氯化聚丙烯的研究   总被引:11,自引:0,他引:11  
采用溶液法用马来酸酐对氯化聚丙烯接枝改性。考察了反应温度、引发剂浓度、单体浓度、溶剂用量等因素对接枝率的影响,测定了反应前后氯含量的变化。采用FT-IR和DSC对产物进行了表征。  相似文献   

10.
碳纳米管的羟甲基化及其马来酸酐接枝研究   总被引:1,自引:0,他引:1  
利用甲醛的亲电性能, 对化学气相沉积法(CVD)制备的多壁碳纳米管(MWCNTs)进行羟甲基化, 并在此基础上酯化接枝马来酸酐, 运用透射电子显微镜(TEM)、红外光谱和Zeta电位仪表征了改性后的MWCNTs的表面结构. TEM结果显示, 酯化后的MWCNTs明显增粗, 说明表面已附有物质. 红外结果表明, 羟甲基后的MWCNTs的表面有了羟基和亚甲基, 而马来酸酐酯化接枝后的MWCNTs有亚甲基和酯基官能团. 光学图像分析表明, 经甲醛处理后的MWCNTs在水溶液中的分散性明显提高, 而马来酸酐酯化接枝后的MWCNTs在二甲苯中的分散性明显增强. Zeta电位的测试结果表明, 甲醛处理过的MWCNTs颗粒在水中, 负电荷增多, 增强了其在悬浮液在溶液中的稳定性.  相似文献   

11.
This work deals with the molecular characterization of maleic anhydride melt-functionalized polypropylene (PP-g-MA). The functionalization mechanism, the nature, the concentration, and the location of grafted anhydride species onto the polypropylene chain are discussed. The polypropylene functionalization was performed using a pre-heated Brabender Plastograph (190°C, 4 min of mixing time). Several concentrations of maleic anhydride and organic peroxide were used for this study. In those experimental conditions, the organic peroxide undergoes an homolytic rupture and carries out a polypropylene tertiary hydrogen abstraction. The resulting macroradical undergoes a β-scission leading to a radical chain end which reacts with maleic anhydride. When a termination reaction occurs at this first step a succinic type anhydride chain end is obtained. However, oligomerization of maleic anhydride is found to occur more frequently leading to poly (maleic anhydride) chain end. Concentration of both anhydride types and minimal length of the grafted poly (maleic anhydride) were determined. A fraction of maleic anhydride does not react with polypropylene or homopolymerize leading to nongrafted poly (maleic anhydride). © 1995 John Wiley & Sons, Inc.  相似文献   

12.
Spherical polyethylene/polypropylene (PE/PP) in-reactor blend granules with various ethylene/propylene molar ratios and high porosity were synthesized using a high yield TiCl4/MgCl2 supported catalyst. A solution of benzoyl peroxide (BPO)/maleic anhydride (MAH)/xylene (interfacial reagent) or BPO/MAH/St (comonomer) was absorbed onto the PE/PP inreactor blend granules, and solid phase gratt polymerization of MAH on PE/PP was conducted. The amount of grafted MAH on PE/PP was measured through chemical titration. The results showed that solid phase graft polymerization of MAH in PE/PP in-reactor blend granules produced graft copolymer with high amount of grafted MAH, and the amount of grafted MAH was raised slightly when St was introduced as comonomer. The graft in-reactor blend was fractionated into five fractions through temperature-gradient extraction fractionation (TGEF), and the fractions were analyzed by FTIR. The results revealed that MAH is mainly grafted on the PE segments, whereas MAH was predominantly grafted on the PP segments when St was present in the graft polymerization system. In addition, the final product is still in the form of regular spherical granules, which is beneficial for industrial processing.  相似文献   

13.
A series of 13C‐enriched maleic anhydride grafted isotactic polypropylene samples were prepared in solution at 170 °C by changes in the initial maleic anhydride content. The NMR spectra of the samples showed that the signals of the maleic anhydride attached to the tertiary carbons of the isotactic polypropylene chains increased considerably with increasing maleic anhydride content, whereas the signals of the maleic anhydride on the radical chain ends (with a single bond) arising from β scission did not. On the other hand, the signals of the maleic anhydride on the radical chain ends with double bonds increased markedly with increasing maleic anhydride content, and this suggested that β scission could occur extensively after maleic anhydride was attached to the tertiary carbons. As a result, the molecular weight of the grafted polypropylene decreased significantly with increasing maleic anhydride content in this study. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5529–5534, 2005  相似文献   

14.
This work investigated the ability of several kinds of molecules to mediate the melt functionalization of polypropylene. N-Bromosuccinimide, nitroxides, iniferters, thiols and RAFT chain transfer agents were tested as potential mediators. The grafting of maleic anhydride onto polypropylene was carried out with and without mediator and the grafted polymers are discussed in terms of graft content, graft structure and molecular weights.  相似文献   

15.
This study reports a reactive extrusion process leading to very high levels of anhydride grafting (2.5–3 wt %) along polypropylene backbone without recovering grafted PP waxes at the die exit. Such high graftings are attainable without excessive degradation of the PP chain by using a brominated reagent. Simultaneously, this brominated reagent allows the tuning of the grafted PP crystallinity via epimerization of the PP backbone. Indeed, the synthesis of a mainly isotactic/atactic stereoblock polymer containing high levels of grafted succinic anhydride moieties is demonstrated by NMR and melting enthalpies recorded by DSC are definitely observed depressed and broadened. Grafting levels of around 3 wt % have been achieved and ascertained by both chemical titration and NMR spectroscopy. In addition, FTIR spectroscopy reveals an unusual observation: for the first time, only one single pair of symmetric and asymmetric carbonyl stretching bands are observed on those grafted PP, while, in other processes of anhydride grafting, those symmetric and asymmetric bands were both split in at least two bands. This suggests, for the here reported process, the absence of interacting grafted anhydride rings, i.e., absence of closely grafted anhydride moieties and absence of poly(maleic anhydride). All those observations support that this “bromine route” brings a really new grafting process for PP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2936–2947, 2008  相似文献   

16.
Radiation-induced copolymer grafting of acenaphthylene and maleic anhydride onto polyethylene or EVA film in the vapor phase was carried out and the effect of comonomer sorption on the grafting was studied. When polyethylene film was used as a backbone polymer, the sorption of the binary monomers during the grafting increased linearly as the grafting reaction proceeded. The marked increase was probably caused by the formation of a grafted layer. Particularly, the sorption of maleic anhydride was brought about by the existence of a grafted layer. In grafting onto EVA film, the content of maleic anhddride in the grafted copolymer increased with the increasing content of vinyl acetate in EVA. Continuous measurements of sorption of the comonomers onto EVA and grafted EVA films were carried out by use of an electrobalance. The distinctive feature of the sorption was that the equilibrium sorption of acenaphthylene or maleic anhydride onto the grafted EVA film increased and the diffusion constants for both comonomers decreased markedly with increasing percentage of graft. The copolymer grafting was explained from these results by assuming that the monomer molecules are supplied to the propagating chain ends mostly through a sorbed state on the polymer film.  相似文献   

17.
The grafting of maleic anhydride onto carbon black surface based on the Diels–Alder addition via ultrasonic irradiation was investigated. Fourier transform infrared spectroscopy (FT‐IR) and thermogravimetric analysis (TGA) were used to determine the chemical structure of the resulting products. The anhydride ring in the modified products can be opened into two carboxylic groups. Accordingly, the carboxylated carbon black was analyzed quantitatively through acid‐based titration to determine the concentration of anhydride ring on the modified carbon black's surface. The grafted molecules amount calculated from the concentration of the anhydride ring was consistent with the results of TGA data. Comparison of zeta potential measurement demonstrated that there were more negative charges attached to the surface of carbon black after ultrasonic modification. TEM observations showed that the conglomeration degree of modified carbon black decreased more than that of initial carbon black. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

18.
Polypropylene ionic thermoplastic elastomers have been prepared by melt radical grafting of maleic anhydride onto polypropylene in the presence of N-bromosuccinimide followed by neutralization of the resulting elastomeric grafted polypropylene using sodium salts. Sodium hydroxide and sodium acetate were compared in aqueous solution, as anhydrous or hydrated powders. The neutralization reaction was followed by Fourier transform infrared spectroscopy, allowing the development of a method to determine the effective neutralization degree. Important physical changes were recorded upon neutralization. Especially thermal stability, shear storage modulus and complex viscosity in the flow region were largely increased as a function of the neutralization degree.  相似文献   

19.
A novel mechanochemical method of preparation of maleic anhydride grafted polypropylene (MAPP) was developed. The preparation was performed by ball milling of polypropylene (PP) powder, maleic anhydride (MA), and peroxide initiator in balls-containing jars with a planetary ball mill for a certain time. Compared with the conventional melt-mixing method, MAPP obtained through ball-milling technique reveals higher graft degree, particularly alleviated degradation of PP, or even increased molecular mass of the resulting MAPP. Maleic anhydride grafted polyethylene (MAPE) was obtained via this technique, and the optimization of the technique is in progress. The novel technique offers new opportunities in modification of polyolefins, which has also the advantages of solventless, lower process temperature, energy efficient, low cost, and simple running process. Furthermore, it is very easy to obtain purified products.  相似文献   

20.
The preparation of a fiber‐forming blend consisting of polypropylene and polyvinyl alcohol mixed with glycerol and with polypropylene grafted with maleic anhydride were studied. The physical and mechanical properties of blend fibers were also studied. The rheological measurements for semiquantitative evaluation of technological compatibility of the components and for processing the polymeric material in extruding and spinning process were carried out. The experimental results revealed the technological compatibility of the polypropylene‐polyvinyl alcohol blend in the presence of glycerol and polypropylene grafted with maleic anhydride. The colloidal structure of interface layer is assumed to be in a three‐ or four‐component system. The mixture of polyvinyl alcohol with glycerol allows for the preparation of well spun fiber‐forming polypropylene blends. Polypropylene‐polyvinyl alcohol blend fibers consisting of up to 20% polyvinyl alcohol with sufficient mechanical properties, higher porosity and significantly higher sorption of water than polypropylene fibers alone were prepared. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

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