苯乙烯/二乙烯苯协助马来酸酐熔融接枝聚丙烯研究

采用液-固溶胀的方法将马来酸酐(MAH)、共单体[苯乙烯(St)、二乙烯苯(DVB)]和引发剂过氧化二异丙苯分散到聚丙烯(PP)颗粒内部,利用流变仪研究了共单体协助MAH熔融接枝PP反应,采用红外光谱、热重分析和水接触角对接枝物的结构及性能进行分析,并对接枝反应机理加以探讨。结果表明,在最优反应条件下,添加St时接枝物的MAH接枝率和凝胶率分别为2.25%、1.56%;添加DVB时接枝物的MAH接枝率和凝胶率分别为3.06%、46.31%,并且接枝物的热稳定性和极性均有不同程度提高;接枝机理分析认为,在接枝反应时共单体首先接枝到PP链上,有效抑制了PP的降解,并与MAH主要以共聚形式接枝到PP主链上;DVB在分子结构上比St多了一个碳碳双键,一方面显著提高MAH接枝率,另一方面明显增大接枝PP大分子自由基间双基偶合终止的机会。     

马来酸酐熔融接枝聚丙烯及降解机理研究

用双螺杆挤出机研究了加入助剂和不加助剂的马来酸酐(MAH)对聚丙烯(PP)的熔融接枝改性.采用正交试验优化了熔融接枝工艺条件.用接枝物的熔融流动速率(MI)来表征PP降解程度,系统研究了单体MAH、引发剂过氧化二异丙苯(DCP)和助剂硫代二丙酸二月桂酯(ABX)用量对PP降解的影响.分析了PP降解机理以及助剂ABX抑制PP降解的机理.分析表明PP降解副反应是由引发剂作用下产生的PP大分子自由基和由MAH作用下产生的PP大分子自由基引起的;ABX助剂一方面由于它的供电子基减小了PP发生分子内和分子间自由基的转移反应,类似于负向催化剂的作用,降低了PP降解,另一方面降低了MAH激态分子的活性,也降低了PP的降解.     

有机分散剂协助三单体固相接枝改性聚丙烯研究

以丙烯酸丁酯(BA)、马来酸酐(MAH)和苯乙烯(St)为接枝单体,偶氮二异丁腈(AIBN)为引发剂,一种有机溶剂作分散剂,对聚丙烯(PP)进行固相接枝改性制备接枝共聚物。考察了反应时间、反应温度、引发剂用量等因素对接枝反应的影响,用红外光谱对接枝产物进行了表征。结果表明,当引发剂用量(以PP为100份基准)为0.3份,单体(BA,St,MAH的物质的量比为2:1:1)总投料量为4份(相对PP为100份)时,得到了接枝率为3.26%的接枝产品。单体利用率达到58.75%。     

BMA协助MAH熔融接枝改性聚丙烯

以甲基丙烯酸丁酯(BMA)为共单体,采用熔融挤出法制备了马来酸酐(MAH)接枝聚丙烯(PP)共聚物PP-g-(MAH-BMA)。通过比较水接触角研究了单体配比和用量、引发剂用量及螺杆转速等因素对接枝效果的影响,并与以苯乙烯(St)为共单体和第三单体的接枝PP产物进行了比较。结果表明,以BMA为共单体提高了接枝产物的接枝率,同时能有效抑制PP分子断链降解,产品的凝胶率为零。随着单体用量、引发剂用量和螺杆转速的增加,改性产品的水接触角均出现极小值。当BMA与MAH的物质的量比为1∶1、MAH的含量为PP质量的3%、引发剂DCP含量为PP质量的0.05%、螺杆转速为160 r/min时,接枝共聚物PP-g-(MAH-BMA)水接触角最低为72°,产物极性显著提高。添加苯乙烯形成的三单体接枝物的黏均摩尔质量和熔体质量流动速率与PP-g-(MAH-BMA)相差不多,但其水接触角却有所增加,并生成凝胶。     

GMA/St双组分单体熔融接枝聚丙烯的研究

分别以甲基丙烯酸缩水甘油酯（GMA）和马来酸酐（MAH）为接枝单体，苯乙烯（St）为接枝共单体，过氧化二异丙苯（DCP）为引发剂对聚丙烯（PP）进行熔融接枝，研究了接枝单体的种类、组分配比等因素对PP的接枝率和熔体流动速率等的影响，并研究了接枝PP的力学性能和耐热变形性能。实验结果表明：作为接枝单体，GMA比MAH更具有优越性；双组分单体熔融接枝PP的接枝率和性能优于单组分单体熔融接枝；接枝PP的结晶参数受其接枝率的影响；当PP／GMA／St／DCP=100／6／3／0、3时，PP—g^-（GMA—CO—St）的接枝率最高，力学性能和耐热变形性能最好。     

丙烯酸丁酯、马来酸酐、苯乙烯三单体固相接枝改性聚丙烯的研究

以丙烯酸丁酯（BA）、马来酸酐（MAH）和苯乙烯（St）为接枝单体,偶氮二异丁腈（AIBN）为引发剂,加入少量有机溶剂作分散剂,对聚丙烯进行固相接枝改性制备接枝共聚物。考察了反应时间、反应温度、引发剂用量等因素对接枝反应的影响,用红外光谱对接枝产物进行了表征。结果表明,当引发剂用量（以PP质量为基准）为0．3％,单体（n（BA）：n（St）：n（MAH）=2：1：1）总投料量为4％时,得到了接枝率为3．26％的接枝产品。单体利用率达到70％。     

聚丙烯熔融接枝马来酸酐和苯乙烯的研究

用双螺杆挤出机研究了加入助剂和不加助剂的马来酸酐(MAH))和苯乙烯(St)对聚丙烯(PP)的熔融接枝改性.采用正交试验优化了熔融接枝工艺条件.系统研究了单体MAH、St,引发剂过氧化二异丙苯(DCP)和助剂 - 一种硫代酸酯(AB)用量对MAH接枝率的影响,并对其影响因素作了分析.用FTIR表征了产物结构.分析了助剂AB抑制PP降解的机理.研究表明AB助剂不仅能降低PP降解,同时也提高了MAH的接枝率.得出较佳的工艺条件为:反应挤出温度T1 = 190℃,T2 =190℃,停留时间t = 2.5 min,转速r = 100r(min(1,较佳的原料质量配比为m(PP):m(MAH): m(St):m(DCP):m(AB)=100:8:3:0.5:0.5.     

多单体固相接枝聚丙烯

用乙醚作分散剂,将接枝单体和引发剂均匀分布到聚丙烯(PP)粒子表面,改善相间传质;以偶氮二异丁腈为引发剂,用固相接枝方法制备了丙烯酸丁酯(BA)-马来酸酐(MAH)-苯乙烯(St)接枝PP。考察了接枝单体用量、引发剂用量、反应温度及时间、界面剂用量等对接枝的影响,用傅里叶变换红外光谱仪、热重分析仪和扫描电子显微镜等对接枝产物进行了表征。结果表明:使用分散剂消除了普通固相反应出现的结块现象,接枝单体分布比较均匀;PP为20.0 g时,n(BA)/n(MAH)/n(St)为2:1:1,接枝单体质量分数为6%,引发剂质量分数为0.3%,在80℃反应1.5 h,得到了接枝率为3.48%的接枝产物;产物的拉伸强度没有变化,但极性和热稳定性得到提高。     

聚丙烯水相悬浮接枝双单体苯乙烯和马来酸酐

以过氧化苯甲酰(BPO)为引发剂,采用水相悬浮法制备苯乙烯(St)、马来酸酐(MAH)双单体接枝聚丙烯共聚物(PP-g-St/MAH),结果表明,较优的接枝反应条件为BPO/St/MAH/水/PP投料质量比0.04/1.00/1.00/25.00/10.00,60℃溶胀2 h后90℃反应5 h.在此条件下,产物接枝率为8.97%,接枝效率为44.85%.     

加入助剂的马来酸酐熔融接枝聚丙烯研究

用双螺杆挤出机研究了马来酸酐 (MAH)对聚丙烯 (PP)的自由基熔融接枝。采用正交试验优化了熔融接枝条件 ,系统研究了引发剂过氧化二异丙苯 (DCP)、单体MAH、助剂ABX用量对马来酸酐接枝率的影响 ,并对其影响因素作了分析。研究表明ABX助剂能降低PP降解 ,同时也提高了马来酸酐的接枝率。确定了较佳的原料配比为m(PP)∶m(MAH)∶m(DCP)∶m(ABX)=1 0 0∶4∶0 4∶0 35。     

Synthesis and characterization of solid‐phase graft copolymer of polypropylene with styrene and maleic anhydride

Polypropylene (PP) was modified by solid‐phase graft copolymerization with maleic anhydride (MAH) and styrene (St), using benzoyl peroxide as the initiator and xylene as the interfacial agent. Effects of various factors such as monomer concentration, monomer ratio, initiator concentration on grafting percentage, and acid value were investigated. The graft copolymer was characterized by Fourier transform infrared, pyrolysis gas chromatography—mass spectroscopy, and dynamic mechanical analysis, and the intrinsic viscosity of the extractive from the reaction product was investigated. The results showed that the grafting percentage and acid value of the graft copolymer of PP with two monomers (MAH and St) were considerably higher than those of the graft copolymer of PP with MAH alone. The graft segments were shown to be the copolymer of St and MAH with a substantial molecular weight. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2482–2487, 2000     

马来酸酐改性聚丙烯的交联副反应

用加入助剂和不加助剂的马来酸酐(MAH)熔融接枝改性聚丙烯(PP)。研究了单体MAH、引发剂过氧化二异丙苯(DCP)和助剂亚磷酸三苯酯(TPP)用量对PP交联的影响。PP交联副反应是由DCP引发生成的PP大分子自由基和由MAH激态分子生成的PP大分子自由基而产生的。TPP含有给电子体,可减小PP分子中甲基产生的正电诱导效应倾向,阻止PP发生分子内自由基的转移反应和分子间的转移反应,减小PP的交联;TPP化合物中含有磷原子,它与MAH的激态分子产生电子转移作用,使MAH的激态分子浓度减小,从而减少PP的交联。     

Enhancement of graft yield and control of degradation during polypropylene maleation in the presence of polyfunctional monomer

Free‐radical initiated grafting of maleic anhydride (MAH)/polyfunctional acrylate (PFA) multimonomer system onto polypropylene (PP) via reactive extrusion was studied. The effects of PFA and initiator concentration on the grafting reaction were investigated. It was shown that PFA as a comonomer could greatly enhance MAH grafting degree, which increased monotonically as the molar ratio of PFA to MAH increased. The rheology test demonstrated that the viscosity of grafted PP was also promoted as more PFA was used. The formation of branched structure during the grafting process was proved by oscillatory shear rheological analysis. The mechanism of grafting in the presence of PFA was discussed, suggesting PFA had higher reactivity with PP macroradicals than MAH and therefore forming stabilized macroradicals, thus resulting in depression of β‐scission and favoring the formation of branched structure. Higher initiator concentration gave higher MAH grafting degree but more severe degradation. The mechanical properties of the grafted PP were comparable with those of unmodified PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

马来酸酐苯乙烯双单体接枝聚丙烯的研究

研究了聚丙烯（ＰＰ）采用熔融法接枝马来酸酐（ＭＡＨ）聚乙烯（Ｓｔ）双单体。实验表明,马来酸酐接枝率随其加入量增加而提高;添加两种单体时,马来酸酐添加量保持不变,马来酸酐接枝率随苯乙烯添加量增加而提高。经转矩流变,红外,热失重和差示扫描量热分析表明：马来酸酐,苯乙烯均与聚丙烯发生接枝反应,且有交联网络出现,因此推断出苯乙烯和马来酸酐预先发生交替共聚,共聚物与聚丙烯反应生成最终接枝物。接枝物应用于ＰＰ     

聚丙烯（PP）／黏土复合材料熔融剂的研究

以马来酸酐（MAH）等为单体接枝聚丙烯作为聚丙烯（PP）／黏土复合材料熔融剂,考察了马来酸酐用量、引发剂过氧化苯甲酰（BPO）用量、反应时间、温度等因素对产物接枝率的影响,并通过红外光谱图对PP-g-MAH进行表征。结果表明,当m（PP）：m（复配单体）：m（BPO）=10．0：2．0：0．6、反应温度控制在120℃左右、复配单体为马来酸酐／苯乙烯时,熔融剂PP-g-MAH的接枝率可获得较大值3．9％。实验同时表明,反应时间对接枝率的影响不大;苯乙烯的加入对接枝率有较大的影响,与普通单体单一马来酸酐相比,加入苯乙烯的接枝率明显提高。     

超临界CO2中聚丙烯接枝改性研究

研究了低温下聚丙烯(PP)在超临界二氧化碳中表面接枝的反应工艺,以过氧化苯甲酰(BPO)作为引发剂,以马来酸酐(MAH)作为接枝单体,对PP进行固相接枝改性,探讨了各种因素对接枝率的影响。结果表明,在低温(60~70℃)下,温度变化对接枝率的影响不明显,其他因素对接枝率影响呈抛物线趋势。最佳接枝工艺条件为:PP 5 g,BPO 0.2 g,MAH1 g,在温度70℃、压力14 M Pa下,反应8 h。     

Styrene‐assisted free‐radical graft copolymerization of maleic anhydride onto polypropylene in supercritical carbon dioxide

The free‐radical graft copolymerization of maleic anhydride (MAH) onto polypropylene (PP) with the assistance of styrene (St) in supercritical carbon dioxide (CO₂) was studied. The effects of the St concentration and initiator concentration on the functionality degree of the grafted PP in supercritical CO₂ were investigated. The addition of St drastically increased the MAH functionality degree, which reached a maximum when the molar ratio of MAH and St was 1:1. St, an electron‐donating monomer, could interact with MAH through charge‐transfer complexes to form the St–MAH copolymer (SMA), which could then react with PP macroradicals to produce branches by termination between radicals. There was SMA in the grafting reaction system characterized by Fourier transform infrared and differential scanning calorimetry. Furthermore, the highest MAH functionality degree was obtained when the concentration of 2,2′‐azobisisobutyronitrile (AIBN) was 0.6 wt % based on PP. The effects of the temperature and pressure of supercritical CO₂ on the functionality degree of the grafted PP were analyzed. An increase in the temperature accelerated the decomposition rate constant of AIBN, thereby promoting the grafting reaction. In addition, an increase in the temperature increased the diffusion of monomers and radicals in the disperse reaction system of supercritical CO₂. The highest degree of functionality was found at 80°C. Also, the functionality degree of grafted PP decreased with an increase in the pressure of supercritical CO₂ within the experimental range. The morphologies of pure PP and grafted PP were significantly different under polarizing optical microscopy. The PP spherulites were about 38 μm in size, and the grafted PP spherulites were significantly reduced because of heterogeneous nucleation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 853–860, 2003     

改性PP的研究与应用

用马来酸酐(MAH)对聚丙烯(PP)进行接枝改性,制得改性PP膜。系统研究了反应温度、反应时间、引发剂(过氧化二苯甲酰)和单体(MAH)等对PP膜接枝率的影响。结果表明:改性后的PP膜性能得到提高。     

不同协助技术固相接枝改性聚丙烯的研究

分别采用有机分散剂、溶液浸渍和超临界二氧化碳(SC CO2)协助技术对聚丙烯(PP)进行固相接枝改性。通过自由基聚合制备了PP与马来酸酐(MAH)、丙烯酸(AA)的接枝共聚物(PP-g-MAH/AA),考察了单体投料量、反应时间、反应温度对接枝反应的影响,用傅里叶变换红外光谱(FTIR)对PP-g-MAH/AA进行了表征,并测试了接枝产物的水接触角、热稳定性、熔体流动速率和力学性能。实验结果表明,当单体投料量为6%,100℃下反应2h时,三种协助方法的接枝效率均达到最大值,SC CO2协助技术对PP接枝改性的接枝率和接枝效率较最高,可达5.33%和88.83%。测试结果表明,SC CO2协助技术制得PP接枝产物热稳定性最好、水接触角最小。     

聚乙烯固相接枝马来酸酐的研究

研究了以过氧化苯甲酰（ＢＰＯ）为引发剂,二甲苯为界面剂,粉状聚乙烯（ＨＤＰＥ、ＬＬＤＰＥ）固相接枝马来酸酐（ＭＡＨ）的反应。讨论了反应温度、引发剂用量、单体用量和界面剂种类等对接枝反应的影响,并用红外光谱法证实了接枝反应。结果表明,ＰＥ固相接枝ＭＡＨ反应对温度敏感,随温度升高,接枝率提高;在一定范围内,接枝率随引发剂用量、单体用量和搅拌转速、界面剂用量的增加而提高;界面剂用量虽少,但能促进ＢＰＯ、ＭＡＨ在ＰＥ上的反应。通过接枝反应可得到接枝率为９％左右的ＰＥ－ｇ－ＭＡＨ产物和接枝率为１３％以上的ＬＬＤＰＥ－ｇ－ＭＡＨ产物