可控流变共聚PP的制备工艺及力学性能

用可控流变法降解共聚聚丙烯(PP)获得可控流变共聚PP。考察了基础树脂、过氧化物加入量、工艺参数对最终产品力学性能的影响。研究发现:在QP73N加入少量过氧化物便能显著改善流动性;根据基础树脂和最终产品的熔体流动指数可确定过氧化物的加入量;各种工艺参数对流变性能的影响由大到小依次为:温度、喂料转速、主机转速;喂料转速与主机转速之比越小,熔体流动指数越高;对降解产品力学性能的各项指标影响最大的因素都是挤出温度,其次是喂料转速和主机转速。     

紫外辐照聚丙烯在熔融挤出中降解过程的研究

研究了聚丙烯(PP)在辐照挤出改性中的降解情况。利用红外光谱对经过不同辐照温度挤出的PP试样进行了结构表征,并通过测定PP试样的熔体质量流动速率、力学性能、DSC和剪切流变行为,分别研究了二苯甲酮(BP)的质量分数、螺杆转速和喂料速度对PP降解的影响,结果表明:辐照温度为210℃更有利于降解反应;不同主机螺杆转速对降解后PP试样的力学性能、熔体质量流动速率、稠度和非牛顿指数的影响不大;喂料速度和BP的用量对降解后PP试样的各项性能影响较大,减慢喂料速度或提高BP的质量分数,有利于PP降解。     

可控流变PP的制备

以抗冲共聚聚丙烯(PP)作为基础树脂,采用可控流变技术制备了不同流动性能的可控流变聚丙烯(CRPP).研究了CRPP与基础树脂性能之间的关系以及CRPP的链结构、结晶行为、相态结构和流变行为.结果表明:高流动CRPP的性能与基础树脂的性能关系密切:可控流变技术难以获得高拉伸断裂应变和高冲击强度的高流动CRPP;降解剂用量为700μg时,CRPP的重均分子量从2.270×10s降至1.351×104,相对分子质量分布从6.49降至4.71;高流动CRPP的相态结构与基础树脂明显不同.     

可控流变共聚PP的刚韧性

考察了工艺条件对抗冲共聚PP可控降解后刚性和韧性的影响.结果表明,在各种工艺参数中温度的影响最大,其次是喂料转速和主机转速,控制好挤出温度足关键;2 000 μg/g滑石粉和300 μg/g成核剂E复配大幅提高产品刚性;通过分析产品的微观形态提出控制好聚合工艺条件和减少在挤出机中的停留时间可提高产品韧性的观点.     

主要工艺参数对三螺杆挤出机流动混合性能的影响

采用Polyflow软件模拟了聚合物熔体PP在三螺杆挤出机计量段内的流动混合过程。借助统计学方法,将累积最大剪切应力分布、累积停留时间分布和混合指数作为评价指标,分析了主要工艺参数(喂料量和转速)对三螺杆挤出机流动混合性能的影响。同时进行PP/EPDM体系共混物制备实验,通过探究工艺参数对分散相粒径及其分布和力学性能的影响以验证数值计算结果。研究结果表明:喂料量和转速增大时,三螺杆挤出机的流动混合性能提高,但当喂料量和转速太大时却不利于三螺杆挤出机的流动混合。     

PP/K树脂合金材料流变行为的研究

借助HAAKERHEOCORD90流变仪分别在200、210、220、230℃4个温度下,研究了PP/K树脂合金材料的流变行为。研究结果表明:PP/K树脂合金材料的流变行为同PP一样,仍属于非牛顿型假塑性流体流动行为。不同剪切速率下,PP/K树脂合金材料黏流活化能比PP小,说明PP/K树脂合金材料的熔体黏度对温度不十分敏感。相同温度下,PP/K树脂合金材料的挤出膨胀比高于PP。PP/K树脂合金材料的熔体流动速率、伸长率、冲击强度明显高于PP。     

可控流变工艺生产无纺布专用PP树脂

选择合适的基础树脂、降解剂,在国产第二代环管聚丙烯(PP)装置上采用可控流变工艺生产无纺布专用树脂。以熔体流动速率(MFR)为(6±1)g/10 min的PP粉料为基础树脂,采用降解剂B成功生产了MFR达(37±7)g/10 min的无纺布专用PP树脂H30S。产品应用试验表明:H30S等规指数大于96.0%,拉伸弹性模量大于1 200 MPa,性能指标优良,用户使用后反馈良好。     

不同喂料工艺对口罩熔喷布用聚丙烯复合材料的性能影响

以均聚聚丙烯(PP)为基体,DTBP过氧化物为引发剂,采用可控降解法制备了口罩熔喷布用PP复合材料。介绍了聚丙烯熔喷PP料改性挤出设备的组成,同时详细介绍了液体引发剂通过主喂料预混添加和平流泵注射添加的不同操作运行工艺,以及不同添加工艺对复合材料性能的影响。结果表明:采用平流泵喂料工艺所制备出来的熔喷PP料,其熔体流动速率MFR稳定可控且DTBP残留物低,经实际生产运行取得了良好的经济效益,得到了客户的高度认可。     

注射工艺对不同熔体流动速率共聚聚丙烯力学性能的影响

在聚丙烯(PP)M20V中添加不同用量的过氧化物,并研究了注射工艺参数对不同熔体流动速率共聚PP力学性能的影响。结果表明:熔体温度、注射速度和保压时间都会影响最终制品的性能。其中,熔体温度对PP的性能影响很大,降低熔体温度,材料的冲击强度大幅提高,拉伸强度增大;提高注射速度,试样的弯曲强度和模量增大;延长保压时间会严重影响产品抗冲击性能。     

可控流变聚丙烯的制备及性能研究

聚丙烯双螺杆挤出过程中加入降解剂进行化学降解,以此方法制备可控流变性能聚丙烯(CRPP)材料.研究降解剂对聚丙烯流动特性、力学性能、综合热性能、分子量及其分布的影响.结果表明,过氧化二叔丁基(DTBP)添加0.47％时,聚丙烯树脂熔体质量流动速率(MFR)达到1 910 g/10min,熔体流动活化能降低到33.71 ...     

PP-R双螺杆挤出熔体输送和降解行为的研究

对无规共聚聚丙烯(PP-R)在ZSK-300型双螺杆挤出机中熔体输送特性和热降解行为进行了研究,计算了ZSK-300的最大挤出量．分析了熔体输送流场;并对加料量、熔体流动指数、助剂量、熔体温度等工艺操作条件对熔体输送和降解行为的影响进行了讨论。结果表明,加料量的改变需要适当调整加热温度：粉料熔体流动指数的微小波动,对挤出物的质量和挤出过程的稳定性没有影响;降低熔体挤出温度,可明显降低PP-R的热氧降解。     

Characterization of high melt strength propylene/1-butene copolymer synthesized by in situ heat induction melt reaction

Propylene/1-butene copolymer powders were produced through bulk copolymerization of propylene with 1-butene in a 12 m³ polymerization reactor. High melt strength polypropylene (HMSPP) was synthesized by in situ heat induction melt reaction, in which pure propylene/1-butene copolymer powders without any additives were used as a basic resin and trimethylolpropane triacrylate (TMPTA) as a crosslinking agent. The structure and properties of the resultant HMSPP were characterized by means of various measurements. The content of TMPTA strongly influenced the melt strength and melt flow rate (MFR) of HMSPP. With increasing the content of TMPTA, the melt strength of HMSPP increased, and the MFR reduced. In addition, owing to the existence of crosslinking structure, thermal stability and tensile strength of HMSPP were improved compared with pristine propylene/1-butene copolymer. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Glycidyl methacrylate–grafted linear low‐density polyethylene fabrication and application for polyester/polyethylene bonding

The grafting of glycidyl methacrylate (GMA) onto linear low‐density polyethylene (LLDPE) was investigated. The grafting was performed by free‐radical grafting in the melt state in a twin‐screw extruder using an organic peroxide as initiator. The effect of initial GMA and peroxide concentration, styrene comonomer addition, as well as initial resin viscosity, on the final content in grafted moieties, unbound homopolymer, and unreacted monomer was assessed. The effect of process parameters such as flow rate, screw rotation speed, and barrel temperature was also investigated. Chemical composition was shown to be the main parameter for controlling grafting level and grafting efficiency. Grafting levels up to 1.8% and efficiency of 90% were reported even though in most conditions, the graft efficiency was severely decreased by the homopolymerization of GMA into polyGMA chains not bound to LLDPE. Finally, the effect of grafting level and the presence of unbound GMA‐based species on the efficiency GMA‐grafted LLDPE as adhesive between polyethylene and polyester were discussed. Good adhesion to poly(ethylene terephthalate) copolymer was found for low viscosity grafted polyethylene resins. A significant improvement in adhesive strength on polyester was observed when the molecular weight of the grafted LLDPE was increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3180–3191, 2004     

ABS/镁盐晶须复合材料的研究

以（乙烯／乙酸乙烯酯／苯乙烯）三元共聚物（BS树脂）为增容荆，采用双螺杆挤出机制备了（丙烯腈／丁二烯／苯乙烯）共聚物（ABs）／镁盐晶须复合材料，研究了BS树脂、镁盐晶须用量对复合材料力学性能、流动性能的影响、结果表明，加入BS树脂有利于提高复合材料的拉伸强度和冲击强度，复合材料的熔体流动速率（MFR）随BS树脂用量增加而增大，且其MFR对温度或负荷呈非线性函数关系，比ABS对负荷更为敏感．     

Functionalization of ethylene–propylene–diene monomer rubber with maleic anhydride in the melt state through high‐shear stress‐induced initiation

The functionalization reactions of ethylene–propylene–diene monomer rubber (EPDM) with maleic anhydride (MAH) in melt state through high‐shear‐stress‐induced initiation by an increase in the screw rotation speed of the twin‐screw extruder and through compounded initiation by the addition of some initiator and an increase in the screw rotation speed were investigated. The results show that, with increasing screw rotation speed and reaction temperature, the percentage grafting and melt flow rate of the functionalized products (EPDM‐g‐MAH) were noticeably increased, and the viscosity‐average molecular weight decreased, which implied that the grafting reaction consisted of the chain scission and grafting reaction of the produced macroradicals with MAH. In the presence of a certain peroxide initiator, the crosslinking reaction during melt extrusion was suppressed by an increase in the screw rotation speed. The percentage grafting of EPDM‐g‐MAH amounted to 1.1%, its melt flow rate was between 0.3 and 4.0 g/10 min, and its gel content was less than 1.0%, depending on the screw rotation speed and reaction temperature. Impact testing and scanning electron microscopy showed that the functionalized product prepared through the high shear stress‐induced initiation had a higher blocking activity with the amide terminated of PA66 than that prepared through the peroxide initiation or through the compound initiation, and the impact strength of the PA66/EPDM blends, improved by the high‐shear‐stress‐induced product was noticeably higher than those of the peroxide‐initiated product or the compound‐initiated one. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

高剪切应力诱导引发马来酸酐官能化三元乙丙橡胶

在熔融挤出过程中,采用提高双螺杆挤出机螺杆转速所产生的高剪切应力诱导引发的方法及添加引发剂与提高螺杆转速的复合引发方法,研究了三元乙丙橡胶(EPDM)与马来酸酐(MAH)的官能化反应.结果表明,双螺杆挤出机的高螺杆转速所产生的高剪切应力作用可诱导EPDM的断链反应,引起官能化产物黏均相对分子质量的明显减小及接枝率与熔体流动速率的明显增大;在适量过氧化物类引发剂存在的条件下,此种高剪切应力作用可抑制EPDM官能化过程中的交联副反应,使产物的凝胶含量明显下降,接枝率及熔体流动速率明显增大;此种官能化反应过程易于控制,可制得接枝率0.80%～1.13%、熔体流动速率0.11～0.28 g/min及凝胶质量分数不大于1.0%的MAH官能化EPDM.     

基于二元接枝单体制备PE⁃HD相容剂、粘接树脂及其性能研究

以双螺杆挤出机熔融挤出为接枝方法,高密度聚乙烯(PE-HD)作为接枝主链,无味过氧化二异丙苯(BIBP)为引发剂,将马来酸二丁酯(DBM)和马来酸酐(MAH)两个极性单体进行复配接枝到PE-HD上,制备含有二元极性单体的相容剂PE-HD-g-(DBM-co-MAH);再将其与PE-HD、线形低密度聚乙烯(PE-LLD)...     

POE⁃g⁃MAH相容剂的制备及其在粘接树脂领域的应用研究

以马来酸酐（MAH）为接枝单体,乙烯?辛烯共聚物（POE）为基体树脂,无味过氧化二异丙苯（BIBP）为引发剂,通过双螺杆挤出机熔融挤出马来酸酐接枝乙烯?辛烯共聚物（POE?g?MAH）,以此作为粘接树脂的相容剂。研究了反应温度、螺杆转速及MAH用量对相容剂熔体流动速率、接枝率的影响,以及相容剂在粘接树脂中的应用。通过熔体流动速率仪、傅里叶红外光谱（FTIR）、万能试验机等对相容剂进行表征和分析;再将相容剂、基体树脂、以及相关助剂通过双螺杆挤出机挤出,得到的粘接树脂通过万能试验机检测其力学性能。结果表明,在引发剂BIBP的作用下,MAH可以顺利接枝到POE上,当MAH的添加量为1 %（质量分数,下同）、BIBP的添加量为0.1 %时,相容剂的接枝率可达0.7 %,熔体流动速率为0.691 g/10 min;在粘接树脂配方中加入20 %的相容剂后,粘接树脂的拉伸强度达到14.8 MPa,断裂伸长率达到1 031.1%,剥离强度达到178 N/25 mm。     

高刚性抗冲共聚PP的开发

结合聚丙烯(PP)装置和产品性能特点,确定了高刚性抗冲共聚PP产品QP73N的技术指标:产品熔体流动速率为8-12 g／10 min,等规指数大于或等于97％、乙烯质量分数为7．0％-9．0％。加工应用试验表明,该树脂在保持较高的刚韧平衡性能的同时,又具有耐翘曲、可明显缩短成型周期等优势。     

Properties of dynamically vulcanized ethylene–propylene–diene copolymer/polypropylene blends

In this study, vulcanized thermoplastic elastomers were produced through the formation of crosslinks with peroxide for different ratios of ethylene–propylene–diene copolymer to polypropylene. Mixing was performed with a twin‐screw extruder. Afterward, the yield, tensile strength, elastic modulus, elongation, Izod impact strength, hardness, melt flow index, Vicat softening point, heat deflection temperature, and density of the crosslinks were determined. The thermal transition temperatures and microstructure were determined with differential scanning calorimetry and scanning electron microscopy, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3895–3902, 2007