聚烯烃熔融接枝改性

熔融接枝技术是聚烯烃改性的一个重要手段,尤其是聚烯烃的挤出熔融接枝技术。本文介绍了聚烯烃熔融接枝的反应机理和动力学模型,以及接枝聚烯烃的定性定量分析测试方法,并探讨了工艺条件、引发剂与接枝单体用量等对聚烯烃接枝率的影响及接枝对聚烯烃结构与性能的影响。     

衣康酸及其衍生物反应挤出改性聚烯烃的研究进展

通过反应挤出的方式, 采用衣康酸及其衍生物对聚烯烃进行接枝改性, 可以显著改善材料性能, 特别是与其他高分子材料的相容性。本文从影响聚烯烃接枝改性的各个因素:聚烯烃类型、引发剂类型以及添加剂出发, 详细论述了国内外研究者的研究进展, 重点阐述了各个因素对聚烯烃改性机理、产物链结构的影响, 认为反应挤出接枝产物链段结构以及螺杆结构对反应挤出的影响这两方面值得进一步研究。     

低密度聚乙烯（LDPE）／马来酸酐（MAH）溶液接枝反应的研究

聚乙烯功能化不仅可改善通用聚乙烯材料的表面粘接性、染色性等，而且可做为聚烯烃材料与其他极性材料（如尼龙类材料）共混相容性的增溶剂。本工作以马来酸酐（ＭＡＨ）为接枝单体，以过氧化二苯甲酰（ＢＰＯ）为引发剂对低密度聚乙烯（ＬＤＰＥ）进行了溶液接枝功能化的研究，考察了实验条件（ＢＰＯ用量，ＭＡＨ用量，反应时间、反应温度、加料方式及反应气氛等）对产物接枝率及特性粘数的影响。     

反应挤出熔融接枝改性淀粉/PE-LD发泡材料的制备及性能研究

将热塑性淀粉分别与6种小分子单体及引发剂熔融挤出制备接枝改性淀粉。红外光谱和接枝率的研究表明,采用熔融挤出接枝的方法可以使小分子单体与淀粉发生接枝反应,丙烯酸与淀粉的接枝率最高为2.4%;采用XRD、哈克流变仪和偏光显微镜等分析了熔融接枝改性淀粉/低密度聚乙烯(PE-LD)共混物的结晶性能、流动性能和发泡性能。结果表明,接枝改性增加了淀粉和 PE-LD 的相容性,使淀粉基发泡材料的密度降低、泡孔均匀度提高,其中用丙烯酸接枝的淀粉/PE-LD 发泡材料的各项性能均较好,丙烯酸的最佳用量为3份。     

通信电缆屏蔽专用树脂的研究

采用熔融挤出法，在引发剂和分散剂的作用下，将马来酸酐（MAH）单体接枝到低密度聚乙烯（LDPE）分子上，制备马来酸酐接枝聚乙烯（MAH－g-PE),用以替代进口的通信电缆屏蔽层专用树脂。并研究了引发剂用量，分散剂种类和用量及螺杆转速对接枝率、熔体流动速率和与铝箔之间剥离强度的影响，从而得出最佳配方。其性能基本接近进口产品，有很大的应用价值。     

熔融挤出接枝法制备HDPE／PA1010增容剂MPE

本文介绍用ＤＣＰＯ作引发剂，通过熔融挤出接枝法制备ＨＤＰＥ／ＰＡ１０１０共混体系增容剂ＭＰＥ的工艺研究。实验结果表明，通过熔融挤出法可将ＭＡＨ单体接枝于ＨＤＰＥ，接枝率和ＭＩ受挤出温度、螺杆转速、ＤＣＰＯ和ＭＡＨ用量的影响，其最佳工艺条件为：挤出温度范围１８０～２２０℃，螺杆转速２５ｒ／ｍｉｎ，ＤＣＰＯ和ＭＡＨ用量分别为０．３份和１．０～１．３份（树脂用量为１００份）。文中还对ＨＤＰＥ融熔挤出接枝     

铝塑复合管用接枝型聚乙烯类热熔胶的制备及性能研究

以高密度聚乙烯（HDPE）和线型低密度聚乙烯（LLDPE）为主体树脂,过氧化二异丙苯（DCP）为引发剂,顺丁烯二酸酐（MAH）为主要单体进行接枝反应挤出制取PE-g-MAH接枝物;然后将该接枝物、增黏剂及其它助剂等进行共混挤出,制备出粘接强度高、流动性能好的铝塑复合管用热熔胶。讨论了原料配比、接枝单体、DCP、增黏树脂和乙烯类弹性体等对该热熔胶性能的影响,并采用红外光谱（FT-IR）技术对该接枝物的结构进行了表征。结果表明：以m（HDPE）∶m（LLDPE）=1∶5,适量控制DCP和不饱和单体的用量,并采用MAH/AA混合单体进行接枝改性,在保证热熔胶流动性能较好的前提下,可得到接枝率及剥离强度均较高的热熔胶;另外,加入适量的乙烯类弹性体,热熔胶的剥离强度明显提高。     

聚烯烃热塑性弹性体POE官能化及其应用

聚烯烃热塑性弹性体（POE）的非极性限制了它的进一步应用,为了扩大其使用领域,对POE官能化引起关注。将POE作为接枝机体树脂,利用其支化度比较高、容易形成接枝点来获得较高的接枝率;由于其侧链相对较大,有可能降低大分子自由基之间碰撞的几率,从而减轻凝胶化程度,得到具有良好流动性的接枝树脂。本文综述了聚烯烃热塑性弹性体POE官能化几种方法,包括在有机过氧化物引发剂存在下的熔融接枝法、裂解引发接枝、机械力引发接枝、复合引发接枝等等,并对其产物的应用进行概括。     

通信电缆屏蔽专用树脂的研究

采用熔融挤出法，在引发剂和分散剂的作用下，将马来酸酐（ＭＡＨ）单体接枝到低密度聚乙烯（ＬＤＰＥ）分子，制备马来酸酐接枝聚乙烯（ＭＡＨ－ｇ－ＰＥ），用以替代进口的通信电缆屏蔽层专用树脂。并研究了引发剂用量、分钐剂种类和用量及螺杆转速对接杆率、熔体流动速率和与铝箔之间剥离强度的影响，从而得出最佳配方。其性能基本接近进口产品，有很大的应用价值。     

SBS接枝型聚烯烃薄膜胶的研究

本文选用ＭＭＡ为接枝单体，对ＳＢＳ进行溶液接枝共聚，并配合增粘树脂制备了对聚烯烃薄膜有良好粘接性能的胶粘剂。探讨了引发剂、反应温度、反应时间及单体用量对接枝共聚的影响，用红外光谱验证了接枝共聚物的存在，并阐述了增粘树脂和抗氧剂的选用原则。     

改性石油树脂对PVC共混改性的研究

用改性后的石油树脂(MPR)与聚氯乙烯进行共混,适量的改性石油树脂不但能显著提高共混物的冲击强度,而且还能改善其加工性能。     

碳纤维表面聚合物接枝改性的研究进展

碳纤维以轻质高强、耐热耐腐蚀、抗蠕变等优点成为十分重要的增强材料。但未经处理的碳纤维表面光滑、呈惰性、界面的粘结性差,需对其表面处理。聚合接枝改性具有不损坏基体、稳定性好且可以接枝特定聚合物等使它成为改性碳纤维的主要方法,详细综述了辐射接枝、光表面接枝、等离子接枝和化学接枝4种聚合接枝改性方法的研究与应用,并比较了它们的优缺点,为碳纤维表面改性研究提供了参考。     

Preparation and performance of new antifouling resins containing BIT group

New acrylate grafting epoxy antifouling resins containing benzoisothiazoline ketone (BIT) group were successfully synthesized, and their structures and performances were determined. Experimental data indicated that the new acrylate grafting epoxy antifouling resins have a strong bonding to the cured epoxy resin coating through chemical reaction and self-stratifying. And the paint prepared by using the new resin as matrix has excellent self-polishing and antifouling properties. Especially its antifouling period could be modified by changing the weight ratio of the usage of the mixed monomers and epoxy resin in the preparing process of the acrylate grafting epoxy antifouling resins.     

High-performance epoxy nanocomposites via constructing rigid structured interphase with epoxy-rich graphene oxide

Epoxy resins, as the most important thermosetting matrix of carbon fiber reinforced polymer (CFRP) composites, are widely used in the structural field, but the highly intrinsic brittleness of epoxy resins greatly limits their application. Therefore, it is urgent to develop new method to prepare high-performance epoxy composites. In this research, GO riched with rigid short-chain structure epoxy group on its surface was synthesized by chemically grafting dopamine, hexachlorocyclotriphosphazene and glycidol successively. Then the modified nanofillers were incorporated into the epoxy matrix to prepare high-performance nanocomposites. The effect of epoxy-rich GO nanosheets as fillers on mechanical properties of aerospace grade epoxy was studied. The results revealed that the epoxy-rich GO could effectively optimize the performance of epoxy resins owing to forming the rigid structured interphase. The tensile strength and elongation at break of the nanocomposites were up to 113 MPa and 7.6% with 0.075 wt% additives, respectively, which greatly surpassed the value reported by the limited researches on strengthening epoxy with GO and its derivate nanofillers. Therefore, instructive idea and effective method were provided to obtain high-performance polymer nanocomposite matrix in this study.     

Synthesis and characterization of hydrogenated sorbic acid grafted dicyclopentadiene tackifier

Hydrocarbon resins, which are defined as low molecular weight, amorphous, and thermoplastic polymers, are widely used as tackifier for various types of adhesives, as processing aids in rubber compounds, and as modifiers for paint and ink products, and for plastics polymers such as isotactic polypropylene. Typically, hydrocarbon resins are non-polar, and thus highly compatible with non-polar rubbers and polymer. However, they are poorly compatible with polar system, such as acrylic copolymer, polyurethanes, and polyamides. Moreover, recently the raw materials of tackifier from naphtha cracking had been decreased because of light feed cracking such as gas cracking. To overcome this problem, in this study, novel hydrocarbon resins were designed to have a highly polar chemical structure. And, it was synthesized by Diels–Alder reaction of dicyclopentadiene monomer and sorbic acid from blueberry as renewable resources. Acrylic resins were formulated with various tackifiers solution including hydrogenated sorbic acid grafted dicyclopentadiene tackifier in acrylic adhesive and rolling ball tack, loop tack, 180° peel adhesion strength, and shear adhesion strength were measured. The properties depend on the softening point and polar content of tackifiers.     

低温增韧尼龙6改性料的研究

研究了在有机过氧化物引发剂(DCP)作用下,马来酸酐(MAH)和聚乙烯在Brabender流变仪中反应接枝,以及接枝母料(PE—g—MAH)的制备方法和工艺。通过化学法测定PE—g—MAH的接枝率(Gx),加入一定接枝率的该母料后,获得适合于扣件挡板座用的尼龙6-聚乙烯共混物的改性材料。     

Hydrophilic polymer supports grafted by poly(ethylene glycol) derivatives via atom transfer radical polymerization

In this study, a newly structured hydrophilic polymer supports are prepared by the chemical modification (grafting) of the polystyrene-based preformed beads via atom transfer radical polymerization (ATRP) employing the CuBr/PMDETA catalyst system. Hydrophilic monomers including N,N-dimethylacrylamide (DMA) and poly(ethylene glycol) (PEG) macromonomers were grafted onto Merrifield type resin. Based on optical microscopic data, the particle sizes of the resins were increased in the order of 10 μm after the polymerization. This increment indicated that monomers are grafted not only to the particle surface but also to within a polymer matrix. These resins demonstrate well-swellability in polar solvent, and they enable high functional loadings up to 0.7-1.8 mmol g⁻¹. The high loading capacity in polar solvents and favorable mechanical properties of resins render them to have great potential applications in peptide and oligonucletide syntheses.     

Studies on α-pinene–furfural-based cation exchange resins. I. Preparation of polymeric compositions and resins

A crosslinked polymer based on α-pinene and furfural suitable for processing into ion exchangers was prepared. The polymer has been processed chemically into different types of cation exchange resins. The role of various parameters such as catalyst concentration, proportion of crosslinking agent, etc., for preparing the polymer is systematically studied and presented. Similarly, the conditions for preparing the various cation exchange resins (sulfonic, phosphonic, and hydroxy phosphonic acid type from the polymer) are also described. A probable/possible composition for the repeating unit in the basic polymer is proposed and supported by experimental evidences.     

高极性PP熔融接枝物的制备及应用

采用复合引发体系、双组分熔融接枝法 ,研制开发了高极性聚丙烯接枝物。讨论了复合引发体系、共聚单体在接枝过程中的作用 ,研究了接枝物对PP/EPDM的相容性的影响。将少量接枝物与PP、EPDM、HDPE共混 ,并添加相容剂及其他助剂 ,可得到高冲击性能、可涂装性能优良的汽车保险杠材料 ,其性能达到国外同类产品指标要求     

Internal stress control in epoxy resins and their composites by material and process tailoring

The development of internal stress during cure of epoxy and hyperbranched polymer-modified epoxy resins was characterized, taking into account the evolving viscoelastic properties, the volumetric shrinkage due to the chemical reaction, and the thermal expansion. A criterion for void formation during cure in a constrained mold was proposed, providing guidelines for the construction of a process window for manufacturing of void-free composites. It was shown that the internal stress development in epoxy resins during cure is strongly influenced by the presence of hyperbranched polymer modifiers. The role of these modifiers was illustrated for the case of autoclave processing of glass fiber/epoxy composites. This study showed that higher fiber volume fractions could be used with hyperbranched polymer-modified resins than with unmodified resins, for producing void-free laminates. It also appeared that by suitable tailoring of the process cycle, a fully stress-free laminate could be obtained after cure, using the modified resin.