Grafting of maleic anhydride onto polypropylene by reactive extrusion

Maleic anhydride grafting onto polypropylene was conducted in a twin‐screw extruder according to an experimental design in which the maleic anhydride and peroxide concentrations were varied. The modified polypropylene was characterized by FTIR spectroscopy, melt‐flow index measurements, size‐exclusion chromatography, differential scanning calorimetry, and nuclear magnetic resonance. The results showed that only the independent variable peroxide concentration influenced the amount of reacted maleic anhydride, whereas the two variables studied influenced the molecular weight of the grafted polypropylene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2706–2717, 2002     

Reactive extrusion of polypropylene with supercritical carbon dioxide: Free radical grafting of maleic anhydride

A reactive extrusion process for the functionalization of polypropylene with maleic anhydride in the presence of supercritical carbon dioxide was studied. Supercritical carbon dioxide was used in this reactive extrusion system to reduce the viscosity of the polypropylene melt phase by forming a polymer–gas solution in order to promote better mixing of the reactants. Subsequently, the effect of supercritical carbon dioxide on the level of grafting, product homogeneity, and molecular weight was evaluated. Analysis of the products revealed that the use of supercritical carbon dioxide led to improved grafting when high levels of maleic anhydride were used. The experimental results showed no evidence of an improvement in the homogeneity of the product, while melt flow rate measurements showed a reduction in the degradation of polypropylene during the grafting reaction when low levels of maleic anhydride were employed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1116–1122, 2003     

Polypropylene degradation control during reactive extrusion

In this work, a proportional‐integral‐derivative (PID) control scheme with two different tuning methods to control the degree of degradation of polypropylene (PP) during reactive extrusion is proposed. The concentration of dicumyl peroxide is taken as the manipulated variable. The molten viscosity of PP under processing is taken as the controlled variable. The degree of degradation is determined by a viscosity function derived by an off‐line identification. A first‐order‐plus‐time‐delay empirical model is identified to simulate the system plant. Both Ziegler–Nichols tuned PID and internal model control (IMC)‐based PID controllers are implemented on the system. Better performances in settling time and precision can be achieved using the IMC‐based PID controller. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 280–289, 2005     

Influence of polyfunctional monomer on melt strength and rheology of long‐chain branched polypropylene by reactive extrusion

Long chain branching (LCB) were added to linear polypropylene (PP) using reactive extrusion in the presence of selected polyfunctional monomers (PFMs) and a peroxide of dibenzoyl peroxide (BPO). Fourier Transformed Infrared spectra (FTIR) directly confirmed the grafting reaction occurred during the reactive extrusion process. Various rheological plots including viscosity curve, storage modulus, Cole‐Cole plot, and Van‐Gurp plots, confirmed that the LCB structure were introduced into modified PPs skeleton after modification. In comparison with linear PP, the branched samples exhibited higher melt strength, lower melt flow index, and the enhancement of crystallization temperature. The LCB level in modified PPs and their melt strength were affected by the type of PFM used and could be controlled by the PFM properties and structure. PFMs with lower boiling points, such as 1, 4‐butanediol diacrylate (BDDA), could not produce LCB structure in modified PP skeleton. The shorter molecular chain bifunctional monomers, such as 1,6‐hexanediol diacrylate (HDDA), favored the branching reaction if their boiling points were above the highest extrusion temperature. And some polar groups, such as hydroxyl, in the molecule of PFM were harmful to the branching reaction, which might be attributed to the harm of the polarity of groups to the dispersion of PFM in PP matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Properties of poly(ethylene terephthalate) and maleic anhydride-grafted polypropylene blends by reactive processing

The properties of poly(ethylene terephthalate) (PET) and polypropylene (PP) blends and PET/maleic anhydride-grafted PP (MAgPP) reactive blends were investigated. Two blend systems were immiscible based on tan δ measured by dynamic mechanical analyzer (DMA). In case of PET/MAgPP blends, the reaction of ester groups of PET and MA sites on MAgPP occurred during melt mixing at 280°C for 30 min. The reaction was confirmed by a new peak between the glass transition temperatures of PET-rich and MAgPP-rich phase on tan δ curves, as well as from the rheological properties. From the morphology, the improvement of the dispersibility in PET/MAgPP reactive blends was observed. The modulus of PET/MAgPP blends was higher than that of PET/PP blends, and the strength of PET/MAgPP blends showed the good adhesion compared with the PET/PP blends. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 389–395, 1998     

聚烯烃接枝马来酸酐的反应挤出研究

研究了聚乙烯（PE），聚丙烯（PP）接枝马来酸酐（MAH）的反应挤出，进行了反应体系的热分析，讨论了引发剂过氧化二异丙苯（DCP）和PE／DCP和PP／DCP体系的影响，以及DCP、MAH和电子给予体（EDA）和LDPE／DCP／MAH和PP／DCP／MAH两种接枝体系的影响。     

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     

氯化聚丙烯及其马来酸酐接枝物的氯含量研究

通过氧瓶燃烧法测定的氯化聚丙烯及其马来酸酐接枝物的氯含量,可以对接枝反应机理和马来酸酐在接枝物中的存在状态进行估计。根据实验所测得的氯含量和接枝率(马来酸酐含量),可以求得接枝物的结构单元。根据结构单元可以计算接枝物结构单元的相对分子质量,这种方法要比用仪器法测定分子质量简单明确。     

聚丙烯接枝马来酸酐的研究

以过氧化二异丙苯（DCP）为引发剂,在双螺杆挤出机中于185—200℃进行了马来酸酐（MAH）熔融接枝聚丙烯（PP）的研究,用红外光谱表征了接枝反应的存在,并得出了吸光比与接枝率的关系曲线。考察了引发剂用量、单体用量对接枝反应的影响,并探讨了二甲基甲酰胺（DMF）的加入对接枝反应的影响。研究表明：DMF不仅能抑制PP的降解,并且当DMF含量在一定范围内时,在反应体系中加入DMF可以提高产物的接枝率。     

反应挤出马来酸酐接枝聚丙烯的结构与性能

选择最佳的配方和工艺条件,制备了每100g试样总酐基含量为8．1mmol的马来酸酐接枝聚丙烯(PP-g-MAH)产品、通过化学分离和红外光谱分析,发现PP-g-MAH产品的纯度很高,几乎没有游离态的MAH。广角X射线衍射实验发现,PP经过接枝处理后,晶型没有改变,但040晶面明显增大;晶胞在a和c轴上变化不大．在b轴上减小;结品度略有上升：通过分析接枝物的流变性能,发现接枝物与PP一样．仍属于非牛顿型假塑性流体。实验证明,PP-g-MAH产品具有良好的可注塑性。     

马来酸酐接枝聚丙烯的方法及其发展

介绍了马来酸酐(MAH)接枝聚丙烯(PP)的方法,主要有熔融接枝、溶液接枝、固相接枝、悬浮接枝等。指出了每种接枝方法的优缺点及研究进展。提出了工业放大、接枝机理的研究以及接枝过程中应考虑经济环保等是接枝技术的发展方向。     

POE/PP体系的反应挤出接枝马来酸酐研究

通过研究辛烯-乙烯共聚物/聚丙烯（POE/PP）比例。第二反应单体的选择，马来酸酐（MAH）单体和过氧化二异丙苯（DCP）用量变化以及反应温度，螺杆转速，真空度对接枝产品性能的影响情况，找出了适合于工业生产的最佳配方和工艺条件，即POE/PP为60：40，MAH为1.5%，DCP为0.04%，提纯苯乙烯为1.5%。螺杆转速为45r/min，真空度为-0.10MPa，螺筒各段温度为160，190（反应段），190（除杂段），150（机头）℃。     

氯化聚丙烯接枝马来酸酐的研究

为了进一步提高氯化聚丙烯接枝马来酸酐的接枝率,优化工艺条件和不同组分的用量,采用正交实验法,研究了马来酸酐(MAH)用量、引发剂过氧化苯甲酰(BPO)用量、反应温度和反应时间对氯化聚丙烯接枝马来酸酐接枝率的影响。结果表明,引发剂BPO用量对接枝率的影响最为明显,而反应时间相对最弱。4种因素的极差递减顺序为:引发剂BPO用量、MAH用量、反应温度和反应时间。     

马来酸酐接枝聚丙烯胶粘剂的合成研究

马来酸酐接枝聚丙烯是一种新型高分子粘合材料 ,其性能取决于马来酸酐在聚丙烯上的接枝率。在以溶剂法进行共聚合时 ,反应温度和引发剂浓度对马来酸酐接枝率有强烈的影响 ,实验表明 ,在温度≤ 10 0℃时 ,马来酸酐接枝率≤ 0 .2 %。在 13 5℃和引发剂用量 3 .0wt%时其接枝率为 1.19% ,同时单体用量对接枝率也有影响。     

聚丙烯固相接枝双单体共聚物的等温结晶行为

用差示扫描量热法结合Avrami方程研究了聚丙烯(PP)与马来酸酐、甲基丙烯酸甲酯双单体固相接枝物的等温结晶行为;用Arrhenius公式分析了接枝支链对PP结晶活化能的影响。研究表明：接枝支链引起PP的结晶成核和结晶生长方式发生变化,既起到异相成核作用,又阻碍了分子链的运动,降低了晶体生长速率。     

聚丙烯塑料胶粘剂的研制

以甲苯为溶剂,过氧化二苯甲酰(BPO)为引发剂,通过自由基聚合,采用马来酸酐(MAH)接枝改性氯化聚丙烯(CPP)；研究了处理条件、固化条件、反应温度、反应时间、MAH的用量、BPO的用量对聚丙烯(PP)塑料胶粘剂粘接性能的影响,得到一种对PP塑料粘接性能较佳的胶粘剂。采用FTIR表征了产品的结构。     

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。     

PP/木粉复合材料的热性能

以聚丙烯(PP)/木粉(WF)复合材料(WPC)为对象,研究了WF及马来酸酐接枝聚丙烯(PP-g-MAH)含量对WPC热性能的影响。PP和WF的熔融热焓分别为75.84 J/g和189.50 J/g,而w(WF)为10%,20%,30%,40%,50%的WPC的熔融热焓分别为54.99,40.37,38.66,27.34,22.09 J/g,加入PP-g-MAH后,WPC熔融热焓值有所提高。所有WPC在200～750℃的热分解都是分两步完成的,WF含量越高,两步分解现象越明显,第一步失重率越大;WPC每步分解的起始分解温度及峰值温度均有所提高,WPC对热更稳定。     

聚乙烯接枝马来酸酐产品的组成和性能

通过反应性挤出可以得到聚乙烯接枝马来酸酐（ＰＥ－ＭＡ）产品。实验发现，ＰＥ－ＭＡ的接枝率（Ｇ）随引发剂ＤＣＰ用量的增加而增加，混合物料在挤出机料筒中停留２ｍｉｎ，接枝反应可充分完成，约有３５％的马来酸酐单体以化学键接枝到聚乙烯分子链上。力学性能的研究表明，ＰＥ－ＭＡ的拉伸强度略高于纯ＰＥ，且随ＰＥ－ＭＡ接枝率的增加而增大。流变学研究表明，ＰＥ－ＭＡ是符合幂律方程的非牛顿假塑性流体。其表观粘度随Ｇ的     

高接枝率PP-g-MAH的制备及其在PP/GF中的应用

对传统双螺杆反应挤出机进行工艺改进,研究了辅助接枝单体和不同半衰期引发剂的分段加入工艺对马来酸酐熔融接枝聚丙烯（PP-g-MAH）的影响。结果表明,辅助接枝单体的提前加入能够有效抑制MAH接枝PP过程中的大分子自由基的断裂;不同半衰期引发剂的分段加入起到良好的协同作用,大幅度提高MAH的接枝效率并有效降低其残留;在30 %玻璃纤维增强PP体系（PP/GF30）中,通过该工艺制备的相容剂在1.6 %的添加量时与通用PP-g-MAH相容剂3 %添加量时的力学性能相近;较低的添加量和MAH残留不仅能够改善最终制品的颜色和气味,还可以提高制品的热稳定性。