马来酸酐固相接枝聚丙烯纤维

了提高非极性聚丙烯纤维(PP)的相容性,采用固相法以马来酸酐(MAH)对聚丙烯纤维进行接枝改性,研究了反应条件对接枝率的影响。结果表明,马来酸酐成功接枝到聚丙烯上,当反应温度为80℃,PP用量为0.5 g,MAH用量为0.2 g,BPO用量为0.05 g,回流时间为2.5 h时,最大接枝率可达到7.51%;BPO的用量、MAH单体的用量以及反应温度对PP纤维的接枝率影响较大。而测定PP纤维接枝率时回流时间对其接枝率的影响不大;接枝聚丙烯纤维的分解温度明显高于纯聚丙烯纤维。     

聚丙烯熔融接枝和预辐射接枝马来酸酐的比较

采用熔融接枝法和预辐射接枝法制备了聚丙烯(PP)接枝马来酸酐(MAH)产物(PP-g-MAH),对这两种不同的接枝方法进行了比较,探索了单体MAH的用量、接枝反应的时间、接枝时的温度等对产物接枝率的影响,接枝率通过化学滴定测得。傅里叶红外光谱仪(FTIR)证实了MAH成功接枝到PP大分子链上。样品表面的元素分析由X射线光电子能谱(XPS)测得。差示扫描量热仪(DSC)及广角X射线衍射仪(WAXD)对所得接枝产物的结晶度及晶型进行了表征。结果表明,熔融接枝和预辐射接枝制得的PP-g-MAH接枝率最高分别为0.43%和0.67%。采用预辐射接枝法制备出的PP-g-MAH接枝率较高,反应操作较为简单。     

聚丙烯纤维共辐射接枝苯乙烯的研究

以60Co γ射线为辐射源,在氮气保护下对聚丙烯(PP)纤维和苯乙烯-二乙烯苯在甲醇介质中进行共辐射接枝。结果表明,当接枝液中苯乙烯质量分数为20％-30％,辐射总剂量为25-50 kGy时,PP纤维的接枝率高。二乙烯苯相对苯乙烯的质量分数为2％时,纤维的接枝率和玻璃化转变温度最高,分别为701％和161.5℃。接枝反应离开辐射源后存在一定程度的后效应,放置一定时间和接枝液中加入适量无机酸均可有效提高PP纤维的接枝率。在相同条件下,用乙醇替代甲醇可以达到相近的接枝率。     

聚丙烯无纺布预辐射接枝改性及胺化研究

采用丙烯酸(AA)、二乙烯三胺(DETA)依次对聚丙烯(PP)无纺布进行预辐射接枝改性及胺化处理,研究了接枝反应及胺化反应的影响因素,并用红外光谱对产物进行表征。结果表明:随着AA用量的增加,接枝率呈先增长后下降趋势;随着反应温度的升高,反应时间的延长,接枝率增加;随着接枝率的增大,胺化反应温度的升高及反应时间的增加,胺化率增加。接枝反应温度为95℃,25 mL AA与无纺布反应2 h,接枝率可达到276%;接枝率为250%的无纺布与50 mL DETA反应7 h,胺化温度205℃,胺化率可达到73%。红外光谱分析表明,经辐射接枝及胺化处理后的PP无纺布有胺基基团。     

聚丙烯纤维接枝苯乙烯的研究

采用化学接枝法以苯乙烯(St)为接枝单体、过氧化苯甲酰(BPO)为引发剂,1,2-二乙烯苯(DVB)为交联剂、甲醇和正辛醇为溶剂,对聚丙烯(PP)纤维进行接枝改性。研究了原料配比和反应条件对其接枝的影响。结果表明,PP纤维上接枝St,适宜的原料配比和操作条件为:St质量与PP体积比(St/PP)为4,BPO质量与St体积比(BPO/St)为0.025,DVB与St体积比(DVB/St)为0.025,溶剂与St体积比为5,浸渍24～30h,在85℃恒温水浴中反应6～8h。在较佳条件下可得到导入率为110%-160%的接枝纤维。     

聚丙烯纤维与4-乙烯基吡啶辐射接枝研究

采用~(60)Coν射线共辐照接枝法,研究了聚丙烯(PP)纤维与4-乙烯基吡啶(4-VP)在甲醇中的接枝共聚反应。讨论了剂量率、辐照时间、单体浓度、阻聚剂以及无机酸对接枝反应的影响。实验获得的接枝共聚物,其亲水性和染色性有明显的改善。     

PP无纺布辐射接枝MMA的研究

采用聚丙烯(PP)无纺布为基材,甲基丙烯酸甲酯(MMA)为单体,~(60)Co-γ射线预辐射接枝共聚的方法制备接枝共聚物,讨论了辐射剂量、反应温度、反应时间、单体浓度、阻聚剂和交联剂的用量等对接枝率的影响。结果表明,接枝反应的最佳条件为:辐射剂量60 kGy以上、接枝温度65℃、接枝时间2 h、MMA质量分数20%、交联剂质量分数5%、阻聚剂用量0．3g,该条件下PP的接枝率为6．5%。     

β晶型PP/纳米CaCO3/短切PET纤维复合材料的制备

通过熔融挤出共混制备β晶型聚丙烯(PP)/纳米CaCO3/对苯二甲酸乙二酯(PET)纤维复合材料,并用马来酸酐(MAH)接枝PP(PP-g-MAH)改善材料的相容性。研究了PET纤维、β成核剂和相容剂对材料力学性能、相容性和结晶熔融行为的影响。结果表明:CaCO3和PET纤维对PP的结晶具有异相成核作用,能协同诱导形成β晶型PP。加入PET纤维可提高材料的刚性和韧性,但会损坏拉伸性能。PP-g-MAH能改善PP和PET纤维之间的相容性,并能促进成核剂在材料中的分散,形成更多的β晶。     

丙烯酸悬浮接枝聚丙烯纤维及性能的研究

借助超声波促进接枝反应的原理,使用二甲苯作为界面剂,使丙烯酸(AA)溶胀渗透到聚丙烯(PP)纤维的表面,以过氧化苯甲酰(BPO)作引发剂,在水溶液中发生悬浮接枝反应。研究单体浓度、反应时间、引发剂和温度等条件对接枝率的影响,并对接枝纤维进行红外和热分析表征。结果发现,接枝纤维有较高的吸湿性能和离子交换当量。反应的最佳条件是:反应温度90℃,反应时间3h,最佳投料比是PP:AA:BPO=1:3:0．02。     

聚丙烯接枝改性综述

本文从能量获取方式介绍了聚丙烯(PP)接枝改性的几种方法,其中包括紫外光接枝法、等离子接枝法、辐射接枝法、熔融接枝法、超临界接枝法、臭氧化接枝法等,并且介绍了各种不同接枝方法的优缺点.并且对聚丙烯接枝改性的发展方向进行了介绍.     

不同单体熔融接枝聚丙烯性能研究

采用双螺杆挤出机熔融接枝的方法,研究了多组分体系下不同单体熔融接枝聚丙烯(PP)的性能。结果表明:在共单体苯乙烯、引发剂和PP相同的条件下,接枝物的极性均较未接枝PP的极性增加,不同单体所得接枝物的接枝率不同。不同熔体质量流动速率造成接枝物的加工性能有不同程度的下降。接枝物极性的增加的趋势依次按接枝单体马来酸酐(MAH)、甲基丙烯酸甲酯(MMA)、甲基丙烯酸缩水甘油酯(GMA)递增。这说明GMA接枝聚丙烯对提高PP极性的效果最明显,MMA其次,而MAH则相对较弱。接枝物的偏光显微镜分析发现,接枝支链的生成可以促进PP的异相成核,造成晶粒细化。     

PP／PP—g—AA／云母复合体系结晶行为的研究

用示差扫描量热分析仪（DSC）、广角X射线（WAXD）的方法研究了PP/PP-g-AA（聚丙烯接枝丙烯酸）/云母复合体系的结晶行为,结果表明：云母、PP-g-AA对聚丙烯具有成核作用,而且云母的用量及PP-g-AA的用量及接枝率对聚丙烯的结晶性能都有影响。     

Synthesis and characterization of macromolecular surface modifier PP--PEG for polypropylene

A novel macromolecular surface modifier, polypropylene-grafted-poly(ethylene glycol) copolymer (PP-g-PEG), was synthesized by coupling polypropylene containing maleic anhydride with monohydroxyl-terminated poly(ethylene glycol). The effects of the reaction condition on the graft reactions were studied. The copolymers were characterized by IR, ¹H NMR, thermogravimetry (TG) and differential scanning calorimetry (DSC). The results indicated that the graft reactions were hindered by increasing the molecular weight of PP or PEG. The graft copolymer was found to have a higher initial thermal degradation temperature and lower crystallization capacity as compared with pure PP, and the side chain of PEG hindered the PP chain from forming a perfect ? crystal. The thermal stability of PP-g-PEG decreased with the increasing content or molecular weight of PEG. The copolymers were blended with polypropylene to modify the surface hydrophilicity of the products. The results of attenuated total reflectance FTIR spectroscopy (ATR-FTIR) showed that PP-g-PEG could diffuse preferably onto the surface of the blends and be suitable as an effectual macromolecular surface modifier for PP.     

Mechanical properties and structural characteristics of dynamically photocrosslinked PP/EPDM blends

The mechanical properties and crystal morphological structures of dynamically photocrosslinked polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) blends have been studied by mechanical tests, wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Dynamically photocrosslinking of PP/EPDM blends can improve the mechanical propertiess considerably, especially the notched Izod impact strength at low temperature. Data obtained from mechanical tests show that the notched Izod impact strength of a dynamically photocrosslinked sample with 30% EPDM at ?20°C is about six times that of an uncrosslinked sample with the same EPDM component. The results from the WAXD, SEM, and DSC measurements reveal the enhanced mechanism of impact strength for the dynamically photocrosslinked PP/EPDM blends as follows: (i) the β‐type crystal structure of PP is formed and the interplanar distance of β‐type crystal increases slightly with an increase in the EPDM component; (ii) the droplet size of the EPDM phase in the photocrosslinked PP/EPDM blends is obviously reduced and the droplet number is increased with an increase in the EPDM component during the dynamical photocrosslinking process; (iii) the graft copolymer of PP‐g‐EPDM is formed at the interface between PP and EPDM components. All the above changes from the crystal morphological structures are favorable for increasing the compatibility and enhancing the toughness of PP/EPDM blends at low temperatures.     

小本体聚丙烯及其接枝丙烯酰胺的非等温结晶动力学

采用DSC方法测试了小本体聚丙烯（PP）及其接枝丙烯酰胺（PP-g-AM）非等温结晶过程的释热情况,并对两组实验数据分别运用Jeziorny法和Mo法进行了处理和比较.结果表明,两种方法均可准确地描述PP及PP-g-AM的非等温结晶过程.PP接枝前后Avrami指数n无明显改变,表明两者结晶机理基本相同;由Jeziorny法得到接枝产物的校正晶体增长速率常数Z_c略大于纯PP的Z_c;由Mo法计算得出,PP-g-AM的F(T)值略小于纯PP的F（T）,表明接枝物的相对结晶速率略大于纯PP的相对结晶速率.     

PP–PP‐g‐MAH–Org‐MMT nanocomposites. I. Intercalation behavior and microstructure

The melt‐direct intercalation method was employed to prepare poly(propylene) (PP)–maleic anhydride grafted poly(propylene) (PP‐g‐MAH)–organic‐montmorillonite (Org‐MMT) nanocomposites. X‐ray diffractometry (XRD) was used to investigate the intercalation effect, crystallite size, and crystal cell parameter in these composites. Two kinds of maleated PP, with graft efficiencies of 0.6 and 0.9 wt %, and two sorts of manufacturing processes were used to prepare nanocomposites and then to investigate their effects on intercalation behavior. The results showed that the intercalation effect was enhanced by increasing the content of PP‐g‐MAH, using maleated PP with higher graft efficiency, and adopting the mold process. The crystallite size of nanocomposites perpendicular to the crystalline plane, such as (040), (130), (111), and (041), reached the minimum value when the content of PP‐g‐MAH was 20 wt %. This result indicated that the crystallite size of PP in nanocomposites decreased by proper addition of PP‐g‐MAH. Maximum values in tensile strength (40.2 MPa) and impact strength (24.3 J/m) were achieved when the content of PP‐g‐MAH was 10 and 20%, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3225–3231, 2003     

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。     

Isotactic polypropylene toughened with poly(acrylonitrile–butadiene–styrene): Compatibilizing role of maleic anhydride grafted polypropylene

The β‐nucleating activity and toughening effect of acrylonitrile–butadiene–styrene (ABS) graft copolymer on isotactic polypropylene (iPP) and the compatibilizing role of maleic anhydride grafted polypropylene (PP‐g‐MAH) on the iPP/ABS blends were investigated. The results show that ABS can induce the formation of β‐crystal in iPP, and its β‐nucleating efficiency depends on its concentration and dispersibility. The relative content of β‐crystal form is up to 36.19% with the addition of 2% ABS. The tensile and impact properties of the iPP were dramatically enhanced by introducing ABS. The incorporation of PP‐g‐MAH into the iPP/ABS blends inhibits the formation of β‐crystal. The crystallization peaks of the blends shift toward higher temperature, due to the heterogeneous nucleation effect of PP‐g‐MAH on iPP. The toughness of iPP/ABS blends improved due to favorable interfacial interaction resulting from the compatibilization of PP‐g‐MAH is significantly better than the β‐crystal toughening effect induced by ABS. POLYM. ENG. SCI., 59:E317–E326, 2019. © 2019 Society of Plastics Engineers     

Morphology and nonisothermal crystallization behavior of PP/Novolac blends

The morphology and nonisothermal crystallization behavior of PP/Novolac blends were studied with scanning electron microscopy, differential scanning calorimeter, polarized optical microscopy (POM), and wide‐angle X‐ray diffraction (WAXD). The results showed that the crystallization of PP in PP/Novolac blends was strongly influenced by cooling rate, size of Novolac particles, crosslinking, and compatibilizer maleic anhydride‐grafted PP (MPP). In dynamically cured PP/MPP/Novolac blends, the MPP grafted on the surface of cured Novolac particles and formed a chemical linkage through the reaction of anhydride groups with the hexamethylenetetramine. The graft copolymer not only improved interfacial compatibility but also acted as an effective heterogeneous nucleating agent, which accelerates the crystallization of PP. The combination of Avrami and Ozawa equations exhibited great advantages in treating the nonisothermal crystallization kinetics in dynamically cured PP/MPP/Novolac blends. The POM results showed that the spherulite morphology and the size of PP in PP/MPP/Novolac blends were greatly affected by Novolac. WAXD experiment demonstrates that the PP and dynamically cured PP/MPP/Novolac blends showed only the α crystal form. At the same time, the addition of Novolac resin also affects the crystal size of PP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Mechanical properties,morphology, and crystal structure of polypropylene/chemically modified attapulgite nanocomposites

Atactic polypropylene (aPP) was chemically grafted onto attapulgite (ATP) via the bridge linking of a polymerizable cationic surfactant and poly(octadecyl acrylate) in the presence of ultrasonic oscillation and dicumyl peroxide, and then, the modified ATP was added to a polypropylene (PP) matrix to obtain PP nanocomposites by melt blending. The results of Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy confirmed that aPP and poly(octadecyl acrylate) were chemically grafted onto ATP through a graft polymerization reaction. The results of the mechanical properties testing showed that the addition of modified ATP improved the toughness and strength of PP remarkably. The dynamic mechanical analysis indicated that the modified ATP significantly increased the storage modulus and decreased the glass‐transition temperature of PP. The results of scanning electron microscopy and transmission electron microscopy showed that the modified ATP was uniformly dispersed into the PP matrix as crystal needles; this proved the presence of strong interactions between modified ATP and PP. The crystal structure analysis revealed that the β‐form crystalline of PP was formed within the modified ATP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011