PTW反应性增容PP/PET热致形状记忆共混合金的性能研究

以乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯三元共聚物(PTW)作为反应性增容剂,采用熔融共混法制备了聚丙烯/聚对苯二甲酸乙二醇酯/PTW(PP/PET/PTW)共混合金。借助扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、万能试验机考察了PTW对PP/PET共混合金相容性、力学性能和热致形状记忆性能的影响。结果表明:少量PTW即可明显改善PP与PET之间的相容性,提高PP/PET共混合金的力学性能和热致形状记忆性能。     

纳米莫来石填充PP/EPDM共混物的脆韧转变

制备了含纳米莫来石的三元乙丙橡胶(EPDM)和马来酸酐接枝三元乙丙橡胶(EPDM-g-MAH)母料,研究了纳米莫来石对聚丙烯(PP)/EPDM和PP/EPDM-g-MAH共混物脆韧转变的影响。结果表明:纳米莫来石的加入使PP/EPDM和PP/EPDM-g-MAH共混物的脆韧转变提前,尤其在纳米莫来石用KH-550改性后,PP/EPDM共混物发生脆韧转变时EPDM的含量由15%降至10%;在橡胶相含量相同时,加入纳米莫来石后共混物的弹性模量和拉伸强度略有下降,而断裂伸长率显著下降。     

三元乙丙橡胶/聚丙烯动态硫化热塑性弹性体的相态结构

用扫描电镜研究了三元乙丙橡胶(EPDM)聚/丙烯(PP)动态硫化热塑性弹性体(TPV)相态结构的形成过程,探讨了交联密度、制备工艺、螺杆转速对EPDM/PP TPV相态结构的影响。结果表明,采用以酚醛树脂为硫化剂的动态硫化工艺制备的EPDM/PP TPV,其相态结构实现了由EPDM和PP组成的双连续相到以EPDM为分散相、PP为连续相的转变;当硫化剂用量为7份时,橡胶相硫化速率和交联密度最大;当螺杆转速为180 r/m in时,反应性挤出工艺较之密炼机工艺制备的EPDM/PP TPV的橡胶粒子更细小、分散更均匀。     

聚丙烯高性能化改性研究

研究了橡胶和弹性体的种类与用量、加工助剂等对聚丙烯(PP)的悬臂梁缺口冲击强度、拉伸强度、硬度、加工性能以及透明性的影响。结果表明:与添加其他橡胶的PP相比,添加乙丙橡胶(EPR)1的PP合金具有较高的悬臂梁缺口冲击强度、透光率及流动性,较低拉伸强度与硬度;添加聚乙烯蜡的PP的综合性能最好。     

PP／EPDM共混合金的结构与性能研究

对聚丙烯(PP)／三元乙丙橡胶(EPDM)共混合金的结构与性能进行了研究。结果表明：国产三元乙丙橡胶J3080P能够大幅度提高PP的常温和低温缺口冲击强度；PP基体的性质和EPDM的用量对增韧效果有明显影响。PP／EPDM共混合金发生脆韧转变所需的EPDM用量为20～30份。EPDM对PP增韧机理遵从银纹-剪切带机理。J3080P对PP的增韧效果优于日本产EPDM 501A。     

增容方法对聚丙烯/亚麻纤维性能的影响

研究了NaOH溶液浸泡亚麻纤维(FF)、添加马来酸酐接枝聚烯烃(MAH-g-PO)、2种方法相结合对聚丙烯(PP)/FF复合材料力学性能及微观结构的影响.结果表明,NaOH溶液浸泡FF后PP/FF复合材料的力学性能有所提高.相对分子质量较大且接枝率较高的马来酸酐接枝聚丙烯(MAH-g-PP)增容效果较好;马来酸酐接枝三元乙丙橡胶(MAH-g-EPDM)和马来酸酐接枝乙烯辛烯共聚物(MAH-g-POE)对PP/FF复合材料起到增容和增韧的作用.NaOH溶液浸泡FF和添加MAH-g-PO相结合的PP/FF复合材料的力学性能好于单独采用一种方法的PP/FF复合材料的.     

KH550改性PEPA对PP/IFR体系阻燃、耐水和力学性能的影响

利用硅烷偶联剂KH550对季戊四醇磷酸酯(PEPA)进行表面改性,得到Si-PEPA,将其与三聚氰胺聚磷酸盐(MPP)复配成膨胀型阻燃剂(IFR)对聚丙烯(PP)进行阻燃改性。研究了KH550改性PEPA对PP/IFR体系阻燃、耐水和力学性能的影响。利用极限氧指数(LOI)仪、垂直燃烧(UL94)仪、锥形量热(CONE)仪对阻燃PP的燃烧性能进行测试,结果表明,当IFR的添加量为20%时,PP/MPP/Si-PEPA体系可以达到UL94 V-0级,氧指数达到32.5%,最大热释放速率(PHRR)和总热释放量(THR)都较PP/MPP/PEPA体系有明显降低。热重分析(TGA)显示,经KH550处理后,PP/IFR材料的热稳定性显著提高。经70℃热水浸泡72 h后,PP/MPP/Si-PEPA材料仍然可以通过UL94 V-1级。同时,KH550对PEPA的表面处理也提高了PP/IFR材料的力学强度。     

超韧聚丙烯的结构与性能

采用扫描电子显微镜、动态力学分析仪和毛细管流变仪等研究了超韧聚丙烯(PP)的结构与性能,并与普通抗冲击共聚PP进行了对比。超韧PP中乙丙橡胶相和PP相的玻璃化转变温度差53.30℃,而普通抗冲击共聚PP中乙丙橡胶相和PP相的玻璃化转变温度差62.32℃;在相同剪切速率下,超韧PP的表观黏度小于普通抗冲击共聚PP;超韧PP在23,-20℃时的简支梁缺口冲击强度分别为70.43,8.55 kJ/m2,远高于普通抗冲击共聚PP(分别为12.00,3.69 kJ/m2)。     

聚甲醛/聚丙烯共混合金的制备及其纤维性能研究

采用双螺杆熔融混炼机共混的方式制备了聚甲醛/聚丙烯(POM/PP)共混合金,探讨了PP含量对共混合金流动性能、热性能、力学性能及纺丝性能的影响。研究结果表明:PP的加入提高了POM/PP共混合金的流动性能和热稳定性,改善了POM的快速冷却结晶特性;当PP加入量为3%时,POM/PP共混合金制得的纤维断裂强度达到最大值728.7 MPa。     

动态硫化对三元乙丙橡胶/聚丙烯共混体系等温结晶行为和形态结构的影响

研究了三元乙丙橡胶/聚丙烯(EPDM/PP)共混物和动态硫化EPDM/PP热塑性弹性体(TPV)的等温结晶行为及形态结构,并用Avrami方程对其进行等温结晶动力学分析。结果表明,EPDM/PP共混物和EPDM/PP TPV的等温结晶行为符合Avrami方程,在相同的结晶温度下,TPV比共混物的Avrami指数小,半结晶时间短,结晶速率常数大;EPDM/PP共混物为双连续相结构,而EPDM/PP TPV是以硫化的细小橡胶颗粒为分散相、PP为连续相的"海-岛"结构,橡胶颗粒尺寸约为0.5μm。     

PP-g-GMA的制备及其改性PP/PA6合金性能

采用双螺杆熔融接枝的方法,在引发剂过氧化二异丙苯(DCP)作用下,将甲基丙烯酸缩水甘油酯(GMA)和共单体苯乙烯(St)接枝到聚丙烯(PP)上。通过傅立叶变换红外光谱仪确定了接枝物的生成,采用酸碱滴定法测定了接枝率。探讨了GMA,St,DCP不同用量对PP接枝物的接枝率和熔体流动速率的影响,并将接枝产物PP–g–(St–co–GMA)加入PP/尼龙6(PA6)的合金中,通过注塑成型样条,测定其力学性能,并观察微观结构。结果表明,St的加入能够提高接枝率,抑制副反应的发生。在PP/PA6合金中加入接枝物PP–g–(St–co–GMA),其拉伸强度可提高46.45%,弯曲强度可提高32.47%,但对冲击强度影响不大。     

Structure and morphology of polyethylene/polypropylene in‐reactor alloys synthesized by spherical high‐yield Ziegler–Natta catalyst

A series of spherical polyethylene/polypropylene (PE/PP) in‐reactor alloys were synthesized with spherical high‐yield Ziegler–Natta catalyst by sequential multistage polymerization in slurry. The morphology of PE/PP alloy granule was evaluated by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results show PE/PP in‐reactor alloy with excellent morphology, high porosity, and narrow distribution of the particle size. The PE/PP in‐reactor alloys show excellent mechanical properties with good balance between toughness and rigidity. It was fractionated into five fractions by temperature‐gradient extraction fractionation, and every fractionation was analyzed by FTIR, ¹³C‐NMR, DSC, and WAXD. The PE/PP in‐reactor alloy was found to contain mainly five portions: PP, PE, segmented copolymer with PP and PE segment of different length, ethylene‐b‐propylene copolymer, and an ethylene–propylene random copolymer. The characteristic chain structure leads to good compatibility between the fractions of the alloy that shows a multiphase structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2075–2085, 2007     

Chain structure of polyethylene/polypropylene in‐reactor alloy synthesized in gas phase with spherical Ziegler–Natta catalyst

Two polyethylene/polypropylene (PE/PP) in‐reactor alloy samples were synthesized by multi‐stage gas‐phase polymerization using a spherical Ziegler–Natta catalyst. The alloys show excellent toughness and stiffness. FTIR, ¹³C‐NMR and thermal analysis proved that the alloys are mainly composed of polyethylene, PE‐block‐PP copolymer and polypropylene. There are also a few percent of ethylene‐propylene segmented copolymer with very low crystallinity. The block copolymer fraction accounts for more than 25 % of the alloy. The role of the block copolymer as compatibilizer between PE and PP is believed to be the key factor that results in the excellent toughness–stiffness balance of the material. Copyright © 2004 Society of Chemical Industry     

β成核剂与乙烯/辛烯共聚物弹性体的协同增韧效应研究

研究了新型稀土β成核剂以及无定形的乙烯／辛烯共聚物弹性体（简称POE）对等规聚丙烯（IPP）增韧改性的协同作用。结果显示,随着成核剂含量的增加,β成核IPP以及β成核IPP／POE共混体系具有相同的变化趋势,POE分散相的存在对1PP体系中的β含量没有明显的影响。不同弹性体含量的共混体系以及各体系在不同温度下的冲击韧性的对比研究表明POE在一定含量时与β成核剂能够获得最大程度的协同效应,在较高POE含量时,二者的协同效应在低温下能够得到较好的表现。     

新型增容剂对PC/PBT合金性能的影响

研究了新型增容剂丙烯酸酯与甲基丙烯酸缩水甘油酯双官能化乙烯类弹性体（KY-6B）对PC／PBT合金性能及结构的影响。结果表明,随着KY-6B含量的增加,PC／PBT合金的拉伸强度、弯曲强度及弯曲弹性模量逐渐降低,而缺口冲击强度、断裂伸长率逐渐提高,非缺口冲击强度变化不大。当KY-6B含量超过10％后,PC／PBT合金的上述性能变化不明显。红外图谱显示,KY-6B的存在使PC与PBT的C=0吸收峰更靠近。差示扫描量热测试结果表明,KY-6B可使PC／PBT合金中PC与PBT两者的Tg之差减小,PBT的熔点、熔融焓、结晶温度有所降低。扫描电镜图谱显示,随KY-6B含量增加,PC／PBT合金的冲击断面逐渐变得粗糙,孔洞化和银纹丝状连接增多。上述结果都表明KY-6B是PC／PBT合金的优良增容剂和抗冲击改性剂。     

PO／PS合金的相态结构与力学性能

以氢化ＳＢＳ（ＳＥＢＳ）为增容剂的聚烯烃／聚苯乙烯（ＰＯ／ＰＳ）合金，与聚烯烃相比具有更好的力学性能，尤其是抗冲击强度随机容剂的增加而大幅度提高，应用ＴＥＭ，ＳＥＭ、ＤＳＣ、偏光显微技术对一系列合金相形态，相容程度及分散相颗粒尺的考察研究发现，合金中分散相多数呈卵石状，随ＳＥＢＳ含量增加，分散相粒径显著变小，而合金抗冲击强度增大，分散相形态结构。颗粒尺寸与材料力学性能密切相联。     

Polypropylene-elastomer (TPO) nanocomposites: 1. Morphology

PP/PP-g-MA/MMT/elastomer nanocomposites were prepared in a twin-screw extruder at fixed 30 wt% elastomer and 0-7 wt% MMT content. The ratio of maleated polypropylene, PP-g-MA and organoclay was maintained at 1. Elastomer particle size and shape in the presence of MMT were evaluated for three different molecular weight grades of polypropylene (PP) and five different ethylene-co-octene elastomers (EOR) with different melt flow index (MFI) and octene contents. The MMT particles are located exclusively in the PP phase in the PP/PP-g-MA/MMT/EOR nanocomposites as seen from TEM images. Injection molded nanocomposite samples show significant decreases in elastomer particle size and increases in elastomer aspect ratio and particle density compared to as-extruded or pelletized samples. The elastomer particle size decreased significantly with increased MMT content and the molecular weight of PP. Low molecular weight PP based nanocomposite showed a greater reduction in elastomer particle size compared to medium and high molecular weight PP based nanocomposites. Elastomers having MFI in the range of 0.5-1.0 gave minimum elastomer particle sizes in the PP/PP-g-MA/MMT/EOR nanocomposite. The elastomer particles were deformed during injection molding leading to an increase in their aspect ratio. The nanocomposites containing high octene content elastomer gave smaller elastomer particle size and higher elastomer aspect ratios compared to nanocomposites containing low octene content elastomer.     

Preparation and characterization of high MFR polypropylene and polypropylene/poly(ethylene‐co‐propylene) in‐reactor alloys

In this work, high melt flow rate (MFR) polypropylene (HF‐PP) and polypropylene/poly(ethylene‐co‐propylene) in‐reactor alloys (HF‐PP/EPR) with MFR ≈ 30 g/10 min were synthesized by spherical MgCl₂‐supported Ziegler–Natta catalyst with cyclohexylmethyldimethoxysilane (CHMDMS) or dicyclopentyldimethoxysilane (DCPDMS) as external donor (De). The effects of De on polymerization activity, chain structure, mechanical properties, and phase morphology of HF‐PP and HF‐PP/EPR were studied. Adding CHMDMS caused more sensitive change of the polymers MFR with H₂ than DCPDMS, and produced PP/EPR alloys containing more random ethylene‐propylene copolymer (r‐EP) and segmented ethylene‐propylene copolymer (s‐EP). CHMDMS also caused formation of s‐EP with higher level of blockiness than DCPDMS. HF‐PP/EPR alloy prepared in the presence of DCPDMS exhibited higher flexural properties but lower impact strength than that prepared with CHMDMS. Toughening efficiency of the rubber phase was nearly the same in the alloys prepared using CHMDMS or DCPDMS as De, but stiffness of the alloy can be improved by using DCPDMS. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42984.     

PA／PP／SEBS三元合金的结构与性能

本文作者采用氢化ＳＢＳ（ＳＥＢＳ）三嵌段热塑性弹性体增韧ＰＡ／ＰＰ共混体系，应用挤出反应技术在双螺杆挤出机内就地产生相容剂，可改善体系的相容性，从而获得了超高韧性的尼龙合金，还采用ＳＥＭ和ＴＥＭ技术研究了此类体系的形态结构特征，这些形态结构为进一步研究结构与性能关系提供了丰富的资料。     

Studies on rheology and morphology of POE/PP thermoplastic elastomer dynamically crosslinked by peroxide

An ethylene‐octene copolymer (POE)/polypropylene (PP) thermoplastic elastomer was prepared through dynamically crosslinking by 2,5‐dimethyl‐2,5‐dilbuty (Peroxy) hexane (DHBP). The effects of DHBP concentration, POE/PP ratio, melt flow index (MFI) of PP, and mixer rotation on rheology and morphology of the thermoplastic elastomer were studied. The results showed that with increasing DHBP concentration or POE content, the size of crosslinked particles as well as the melt viscosity increased. Furthermore, agglomerates or a network structure formed as the size of crosslinked particles increased. The melt viscosity also increased as MFI of PP decreased, while the size of crosslinked particles decreased under the same condition. Research on the morphology of dynamically crosslinked POE/PP thermoplastic elastomer flowing through a capillary rheometer at different shear rates show that the reprocessing had little effect on the morphology of dynamically crosslinked elastomer. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.