Melt rheological properties of polypropylene–maleated polypropylene blends. I. Steady flow by capillary

Melt rheological properties of blends of polypropylene (PP) and PP grafted with maleic anhydride (PP‐g‐MA) are studied using a capillary rheometer. A pseudoplastic flow behavior is observed. The pseudoplasticity of the melt reduces with an increase of PP‐g‐MA content and/or temperature. The PP‐g‐MA component in the blend acts as decreasing melt viscosity, especially in the lower shear rate region, while the addition of PP‐g‐MA to PP does not cause obvious increase of die swell ratio. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1641–1648, 1999     

马来酸酐-丙烯酸酯类共聚物作油煤浆燃料稳定剂研究

以马来酸酐与丙烯酸酯的共聚物为稳定剂,当共聚物中,n(马来酸酐):n(丙烯酸丁酯)=1:5,用吡啶中和,稳定剂的添加量为0.4%时,油煤浆(COM)燃料在3个星期后的棒惯时间仍然小于2 s,碳粉的最高质量含量可达59.4%.该稳定剂用量少、原料易得,有较好的应用前景.     

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。     

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     

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     

溴化丁基橡胶与普通丁基橡胶并用性能之研究

文中对溴化丁基橡胶与普通丁基橡胶并用的目的和意义进行了探讨，对不同比例并用胶料的硫化特性、物理性能、化学性能进行了测试和分析。同时，对并用胶的共硫化系统也作了初步的分析。     

马来酸酐和苯乙烯接枝改性对天然橡胶/聚丙烯共混物物理机械性能的影响

用动态硫化法制备了天然橡胶(NR)/聚丙烯(PP)热塑性弹性体(TPV)。研究了马来酸酐/苯乙烯/过氧化二异丙苯(MAH/St/DCP)多单体熔融接枝交联改性及纳米二氧化硅用量对NR/PP TPV物理机械性能的影响,讨论了NR/PP TPV的重复加工性能。结果表明,当MAH/St/DCP用量为3.750/1.875/0.375质量份、纳米二氧化硅用量为3质量份时,NR/PP TPV的物理机械性能最好,达到了国内外有关通用橡胶/PP TPV的水平,并且具有较好的重复加工性能。     

丁基橡胶及卤化丁基橡胶阻尼材料的研究进展

介绍了丁基橡胶的阻尼性能及应用,阐述了丁基橡胶、氯化丁基橡胶及溴化丁基橡胶阻尼材料的研究进展.指出提高损耗因子和拓宽阻尼温域是丁基橡胶基高性能阻尼材料的研究方向,丁基橡胶与其他橡胶共混、开发合适的硫化体系和填料是提高丁基橡胶基阻尼材料性能的重要手段.     

聚乙烯醇/马来酸酐接枝聚丙烯共混物的热行为研究

采用熔融共混法制备了一种聚乙烯醇(PVA)/马来酸酐接枝聚丙烯(PP-g-MAH)共混物膜,通过差示扫描量热仪研究了共混物膜的结晶和熔融行为。结果表明,随着共混物中PP-g-MAH含量（不超过50 %）的增加,PVA相的结晶和熔融温度升高,结晶度增加,结晶速率增加,而随着PVA含量（超过30 %）的增加,PP-g-MAH的结晶及熔融温度降低,结晶度降低,结晶速率增加。用Ozawa法对共混物中PVA相的非等温结晶动力学研究表明,共混物中PVA相在191~197 ℃开始主期结晶,在173~189 ℃进入次期结晶阶段。     

EPDM橡胶的流变特性实验研究

为了研究橡胶熔体流变性能对其加工成型的影响，利用毛细管流变仪对三元乙丙橡胶（EPDM）的流变特性进行了实验研究。实验结果表明：EPDM橡胶在毛细管挤出时，剪切速率对剪切应力、剪切粘度和挤出胀大的影响最大；挤出温度对三者有一定的影响；在长径比相同时，毛细管半径对剪切应力和剪切粘度几乎没有影响，但对挤出胀大影响较大。     

Thermal and mechanical properties of polypropylene nanocomposite materials reinforced with cellulose nano whiskers

We use polypropylene (PP, an apolar polymer) and cellulose nano whiskers (CNW, a polar material) to produce nano polymer composites with enhanced mechanical and thermal properties. To improve compatibility, maleic anhydride grafted PP has also been used as a coupling agent. To enhance the uniform distribution of CNW in the composite, the matrix polymer is dissolved in toluene, and sonification and magnetic stirring are applied. Good film transparency indicates uniform CNW dispersion, but CNW domains in the composite film observed under an scanning electron microscope may indicate slight agglomeration of CNW in the composite film. The tensile strength of the composite compared with neat PP improves by 70–80% with the addition of CNW. The crystallinity has also been improved by about 50% in the CNW reinforced samples. As the content of CNW increases, the composite exhibits higher thermal degradation temperature, higher hydrophilicity, and higher thermal conductivity. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Flow visualization and extrudate swell of natural rubber in a capillary rheometer: Effect of die/barrel system

An investigation was carried out to examine the effect of die/barrel system on the flow patterns and extrudate swell of natural rubber in the barrel of a capillary rheometer, using a colored tracer as the visualization technique. The capillary rheometer used in this work had two dies located along the barrel, which is novel in rheometer design. The flow of the rubber in the upper barrel was dependent on the piston/barrel action and changed with piston displacement, whereas the complexity of the flow in the lower barrel was dependent not only on the piston displacement, but also on the geometry of the upper die design. The flow patterns that developed in the whole barrel were independent of the die located at the bottom of the barrel. In addition, the change in extrudate swell was associated with the flow occurring in the barrel, residence time, elastic characteristic, and the temperature rise during the flow. It was concluded that the general style of the flow patterns of natural rubber was greatly dependent on the die geometry that the material had previously moved past. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2525–2533, 2001     

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     

Physical properties and cure characteristics of natural rubber/nanoclay composites with two different compatibilizers

The effects of epoxidized natural rubber (ENR) and maleic anhydride‐grafted polybutadiene (PB‐g‐MA) as compatibilizers to rubber formulations with and without organo‐modified layered silicates are investigated. The physical properties and curing characteristics of composites are studied by moving die rheometer, rubber process analyzer, tensile, tear, and hardness testing. The state of organoclay intercalation was determined by X‐ray diffraction method. The addition of compatibilizers, especially ENR 50, results in further intercalation or exfoliation of the organoclay that increased the clay dispersion in the rubber matrix. ENR 50 with organo‐modified clay improves the physical properties and changes the curing profile. The addition of PB‐g‐MA without organoclay increases the tensile strength (σ_max) by increasing the stock viscosity of the rubber compound. Interestingly, simultaneous increase in hardness and σ_max is achieved in the presence of both compatibilizers, a characteristic that is difficult to achieve and sometimes required in rubber processing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of polypropylene‐graft‐maleic anhydride compatibilizer and evaluation of nylon 6/polypropylene blend properties

Polymer blends based on polyolefins are of a great interest owing to their broad spectrum of properties and practical applications. However, because of poor compatibilities of components, most of these systems generally exhibit high interfacial tension, a low degree of dispersion and poor mechanical properties. It is generally accepted that polypropylene (PP) and nylon 6 (N6) are not compatible and that their blending results in poor materials. The compatibility can be improved by the addition of a compatibilizer, and in this study PP was functionalized by maleic anhydride (MAH) in the presence of an optimized amount of dicumyl peroxide (DCP). The reaction was carried out in the molten state using an internal mixer. Then, once the compatibilizer polypropylene‐graft‐maleic anhydride (PP‐g‐MAH) was prepared, it was added at various concentrations (2.5–10 wt%) to 30/70 glass fibre reinforced N6 (GFRN6) PP, and the mechanical properties were evaluated. It was found that the incorporation of the compatibilizer enhanced the tensile properties (tensile strength and modulus) as well as the Izod impact properties of the notched samples. This was attributed to better interfacial adhesion as evidenced by scanning electron microscopy (SEM). The optimum in these properties was achieved at a critical PP‐g‐MAH concentration. Copyright © 2005 Society of Chemical Industry     

用Haake流变仪再生和硫化的废旧丁基橡胶的性能

利用Haake流变仪的高温和剪切作用对废旧丁基橡胶(IIR)进行脱硫,考察了加工温度对再生胶脱硫程度、硫化再生胶力学性能的影响以及废旧IIR、再生胶和硫化再生胶的阻尼性能。结果表明,Haake流变仪能使废旧IIR达到脱硫的目的,当加工温度为200~320℃时,随着加工温度的提高,脱硫程度增大;与废旧IIR相比,再生IIR和硫化再生IIR的阻尼性能有很大程度提高。     

Design of functional macromonomer derivatives of poly(isobutylene‐co‐isoprene)

The development of new peroxide‐curable poly(isobutylene‐co‐isoprene) (IIR) elastomers is described, wherein pendant oligomerizable C=C groups are introduced in combination with a range of serviceable functional groups. Ring‐opening of itaconic anhydride with functional alcohols or amines, followed by esterification of the resulting acids with brominated IIR, yield macromonomers that crosslink efficiently under the action of dicumyl peroxide alone. More importantly, the additional graft functionality improves the physical and chemical properties of the resulting thermosets. The introduction of fluorocarbon functionality is shown to lower surface energy and improve the material's extrusion characteristics, and trialkoxysilane functionality is used to improve filler dispersion within silica‐reinforced composites. This strategy is extended to prepare thermosets bearing polymer‐bound phenolic antioxidant. Details of macromonomer production are followed by demonstrations of their utility as engineering materials.     

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。     

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。