接枝共聚改性氯化聚丙烯乳液的研究

以丙烯酸酯单体作为接枝共聚单体,合成了无芳烃低VOC的CPP(氯化聚丙烯)乳液。以接枝率和耐水性作为衡量指标,采用单因素试验法优选出制备CPP乳液的最佳工艺条件。结果表明:当反应温度为95℃、反应时间为3.5 h、w(总引发剂)=1.0%(其中10%引发剂在滴加单体以前加入,并且间隔时间为10 min)、w(丙烯酸酯单体)=30%和w(丙烯酸)=5%时,相应CPP乳液的综合性能相对较好,并且其对聚丙烯(PP)基材的附着力相对最好。     

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     

等规聚丙烯-丙烯酸接枝共聚

详细研究了等规聚丙烯细粒子在丙烯酸水溶液中,以过氧化苯甲酰为引发剂的液－固相接枝共聚反应和十氢化萘乙醇溶液对等规聚丙烯的膨化预处理作用,检测了等规聚丙烯－聚丙烯酸的某些性质,发现随接枝率提高,其吸湿性和碱性染料染色性均提高,熔点略有降低,但熔体流动性下降,按本研究获得的最佳膨化预处理条件和最佳接枝共聚反应条件,接枝产物等规聚丙烯－聚丙烯酸的接枝率可超过13％。     

聚丙烯固相接枝技术的研究进展

综述了聚丙烯(PP)固相接枝技术的最新发展,重点介绍了PP固相接枝的原理,讨论了接枝单体．接枝基体、引发剂、溶剂．催化剂．反应温度．反应时间对接枝率的影响。PP固相接枝技术在PP复合材料与共混合金中具有良好的使用效果和广阔的应用前景。     

PAE与丙烯酰胺接枝共聚改性的研究

利用溶液聚合的方法，使丙烯酰胺单体与不饱和聚酰胺多胺环氧氯丙烷树脂接枝共聚。在实验过程中，运用单体因素分析的方法，讨论了反应时间、引发剂用量、聚合单体丙烯酰胺的用量等主要因素对接枝共聚反应的影响。接枝后的聚丙烯酰胺树脂除了具有良好的湿拉伸强度性能外，还可以大幅度地提高纸张的干拉伸强度。     

玉米淀粉接枝丙烯酸制备高效吸水树脂的研究

本文在紫外光照射下以芬顿试剂为引发剂,制备玉米淀粉接枝丙烯酸高效吸水树脂。通过单因素法考察了中和度、淀粉与丙烯酸质量比、交联剂及引发剂用量等因素对反应的影响,并通过红外光谱分析仪(FT-IR)对产品结构进行表征。实验结果表明:在N2保护下淀粉乳浓度为5.88%,丙烯酸与淀粉的质量比为1.3∶1,引发剂用量和交联剂用量占淀粉的质量百分数分别为5.00%和2.00%,聚合温度为40℃,聚合反应时间为1h,中和度为65%,所制备淀粉吸水树脂的吸水倍率可达到631g·g-1。     

Structure and mechanism of functional isotactic polypropylene via in situ chlorination graft copolymerization

This paper discusses the structure and mechanism of maleic anhydride (MAH) grafted onto isotactic polypropylene (iPP) via in situ chlorination graft copolymerization (ISCGC). The molecular structure of the grafted iPP was characterized using ¹H NMR and ¹³C NMR spectroscopy, viscosity‐average molecular weight and gel content. The structure of un‐grafted MAH present in the reaction system was investigated using Fourier transform infrared spectroscopy in order to explore the grafting of MAH on iPP. The main side‐reactions, including iPP chain scission and crosslinking, during the grafting reaction were explored. From the experimental results obtained, the reason for controlled macromolecular chain degradation and crosslinking of grafted iPP in ISCGC is proposed. Based on the structural characterization of the grafted polymer, the mechanism of grafting onto iPP obtained via ISCGC was deduced. Mechanical properties, both static and dynamic, of grafted iPP were also investigated and the results showed that the properties of the material changed due to grafted MAH. Copyright © 2011 Society of Chemical Industry     

Radiation‐induced graft copolymerization of 2‐vinylpyridine and styrene onto isotactic polypropylene fiber

Isotactic polypropylene fiber (IPP) was graft‐copolymerized using 2‐vinyl pyridine (2‐VP) and styrene (sty) as the monomers by the mutual irradiation method in air. The percentage of grafting was determined as a function of various reaction parameters and it was found that the maximum grafting of 2‐VP (114%) and sty (76%) was obtained at an optimum dose of 1.08 × 10⁴ and 0.64 × 10⁴ Gy using 1.8 × 10⁻² mol of 2‐VP and 4.3 × 10⁻² mol of sty, respectively. The graft copolymers were characterized by differential scanning calorimetric analysis and isolation of the grafted chains from the grafted iPP samples. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2959–2969, 1999     

Kinetics study on melt grafting copolymerization of LLDPE with acid monomers using reactive extrusion method

Graft copolymerization in the molten state is of fundamental importance as a probe of chemical modification and reactive compatibilization. However, few grafting kinetics studies on reactive extrusion were carried out for the difficulties as expected. In this work, the macromolecular peroxide‐induced grafting of acrylic acid and methyl methacrylate onto linear low density polyethylene by reactive extrusion was chosen as the model system for the kinetics study; the samples were taken out from the barrel at five ports along screw axis and analyzed by FTIR, ¹H NMR, and ESR. For the first time, the time‐evolution of reaction rate, the reaction order, and the activation energy of graft copolymerization and homopolymerization in the twin screw extruder were directly obtained. On the basis of these results, the general reaction mechanism was tentatively proposed. It was demonstrated that an amount of chain propagation free radicals could keep alive for several minutes even the peroxides completely decomposed and the addition of monomer to polymeric radicals was the rate‐controlled step for the graft copolymerization. The results presented here revealed that the relative importance of graft copolymerization compared with homopolymerization mainly depended on the monomer solubility and reactivity, while the process parameters such as reaction temperature also influenced the reaction tendency. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4301–4312, 2006     

Study of modified polypropylene nonwoven cloth. I. graft copolymerization of 4‐vinylpyridine onto polypropylene nonwoven cloth by preirradiation method

Polypropylene (PP) nonwoven cloth was grafted with 4‐vinylpyridine (4‐VP) by a preirradiation method. The effects of preirradiation conditions on the mechanical properties of preirradiated PP nonwoven cloth and the percentage of grafting (Pg) of 4‐VP onto the preirradiated PP nonwoven cloth were systematically investigated. The results indicated that the mechanical properties of preirradiated PP nonwoven cloth decreased with increasing irradiation dose and that the Pg was greatly affected by the concentration of monomer, irradiation dose, grafting reaction temperature, and the addition of inhibitor and inorganic acid in the grafting reaction system. The grafted nonwoven cloth samples were characterized using IR spectroscopy and SEM. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1861–1868, 2000     

聚丙烯的化学接枝改性

综述了聚丙烯常用的化学接枝改性方法,单体和引发剂的选择,接枝率的测定方法以及接枝反应机理,并对接枝共聚物的结构性能作了简要阐述。     

Ceric‐initiated free radical graft copolymerization of acrylonitrile onto kappa carrageenan

The polysaccharide, kappa carrageenan (kC), was modified using ceric‐initiated graft copolymerization of acrylonitrile (AN) under inert atmosphere in a homogeneous aqueous medium. Grafting was confirmed using FTIR spectroscopy, solubility test, elemental analysis, acid hydrolysis, and thermogravimetric analysis (TGA). kC‐graft‐poly(AN) products had a higher thermal stability than kC as revealed by TGA analysis. The polyacrylonitrile branches were isolated by acidic degradation of the carrageenan main chains and characterized by size exclusion chromatography (SEC). Residual monomers were not found by HPLC in graft copolymers stored even for longer periods. The effect of various factors affecting on grafting, i.e., concentration of the initiator, monomer, and polysaccharide as well as the reaction time and temperature were studied by conventional methods to achieve the optimum grafting parameters. The graft copolymerization reactions were kinetically investigated using semi‐empirical expressions and a suitable rate expression has been derived. According to the empirical rates of the polymerization and the graft copolymerization of AN onto kC backbone, the overall activation energy of the graft copolymerization reaction was estimated to be 20.96 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

功能化聚丙烯研究进展

综述了国内外聚丙烯(PP)功能化的方法,主要包括丙烯与极性单体直接共聚法、中介物功能化法、接枝改性法等,重点讨论了后两种功能化方法。通过化学反应在PP分子结构中引入极性基团是达到PP功能化的根本途径。     

羧甲基甲壳素与丙烯酰胺接枝聚合反应研究

制备了羧甲基甲壳素接枝丙烯酰胺共聚物,讨论了反映温度、时间、引发剂用量、溶剂用量、单体用量对接枝反应的影响。最佳反应条件为：羧甲基甲壳素0．4g,溶济水50mL,引发剂60mg,单体1．6g,反应温度50℃,反应时间3．0h。     

Graft copolymerization of methacrylic acid onto isotactic polypropylene by radiochemical methods

Graft copolymerization of methacrylic acid onto isotactic polypropylene has been studied in water–methanol medium using γ-rays as the source of initiation. Graft copolymerization has been conducted by (1) mutual irradiation, (2) preirradiation, and (3) double irradiation methods. All of the reaction parameters that seem to influence grafting have been studied, and the optimum conditions leading to maximum percentage of grafting have been evaluated. A plausible mechanism for radiation-induced grafting of methacrylic acid onto polypropylene has been suggested, and the results have been explained on the basis of the proposed mechanism. A comparative study of graft copolymerization by different radiation methods has been made, and it was observed that the preirradiation method affords the best results. Evidence of grafting has been obtained from differential scanning calorimetric analysis and the dyeing behavior of the grafted material. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 143–152, 1998     

Study of electron beam preirradiation-induced graft copolymerization of acrylic acid onto powdered isotactic polypropylene

In order to obtain required polymer materials, acrylic acid was grafted onto powdered isotactic polypropylene by an electron beam preirradiation technique. All processes (including irradiation, storage of the samples, and grafting polymerization) were carried out in air. The effects of irradiation dose, storage time, reaction temperature, morh's salt, acid, and monomer concentration were investigated and discussed in detail. The results show that the grafting can be achieved well without purging oxygen, and morh's salt is indispensable for initiating grafting reaction and decreasing the homopolymerization. Optimal reaction conditions can be generalized for large-scale production of the desired polymer materials. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1357–1362, 1999     

羧甲基甲壳素接枝丙烯酸丁酯共聚物的制备及水溶性

制备了羧甲基甲壳素接枝丙烯酸丁酯共聚物,讨论了反应温度、时间、引发剂用量、溶剂用量、单体用量对接枝反应的影响。最佳反应条件为:羧甲基甲壳素0.3g,溶剂水30mL,引发剂50mg,单体1.2g,反应温度60℃,反应时间3.5h。用红外光谱对接枝产物进行了表征,考察了不同接枝率的产物在10种常见溶剂中的溶解性,结果表明不同接枝率的接枝产物都有水溶性。     

接枝共聚改性脱脂豆粉胶粘剂的研究

脱脂豆粉悬浮液经脲预处理后,以APS—NaHSO3氧化还原体系为引发体系,通过自由基聚合,采用BMA接枝共聚改性。研究了反应条件对接枝共聚改性脱脂豆粉胶粘剂的T剥离强度和耐水性的影响,得出较佳工艺条件为:BMA/SPI:50%,APS/BMA:0.6%,NaHSO3/APS:1/1.5,接枝时间:3h,接枝温度:80℃。此条件下的T剥离强度为130.6N/m,约为最小值的两倍,耐水性为50.55%。     

Studies on graft copolymerization of cyclohexyl methacrylate onto chloroprene rubber

Graft copolymerization of cyclohexyl methacrylate (CMA) onto chloroprene rubber (CR) was carried out in toluene using benzoyl peroxide as an initiator. The graft copolymer was isolated from the gross polymer by extracting it with a butanone solution. Infrared (IR) spectra of the graft copolymer showed the occurrence of grafting. Optimization of various parameters of the grafting, namely, time, temperature, and initiator concentrations, was performed. The mechanical adhesive properties of the graft copolymer, CR-g-CMA, were measured and compared with those of the graft copolymer of methyl methacrylate (MMA) onto CR, CR-g-MMA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1733–1737, 1997