用于聚乙烯表面改性的紫外光接枝技术

从STS角度出发,结合新课标高中化学高分子知识,介绍一种聚乙烯表面改性技术--紫外光接枝技术,供一线高中化学教师用于拓展高中生的高分子化学知识。     

等离子体辐照的聚乙烯表面接枝交联共聚合

聚合物利用低温等离子体预辐照进行表面接枝共聚合已有报道.此方法的优点是接枝层被限制在聚合物表面,辐照过程对基材本体性质无影响,且整个过程对环境无污染. 用等离子体使聚合物表面产生自由基,不需要表面具有不饱和键或特殊官能团,因而适用于任何聚合物,甚至于一些无机物如玻璃等.利用等离子辐照后暴露于空气的聚合物表面上生成的过氧自由基或过氧化物进行接枝反应,一般接枝量不大.本工作中,我们自己设计了反应器,以超高分子量聚乙烯(UHMWPE)为基材,以甲基丙烯酸甲酯(MMA)为接枝单体,在无氧条件下利用等离子体辐照产生的表面自由基进行了接枝聚合,产物接枝量高达10％.还用顺磁共振技术对表面自由基性质及其在接枝过程中的行为进行了跟踪研究.     

聚氯乙烯表面共价键合肝素及抗凝血性的研究

采用Ar等离子体引发聚乙二醇(PEG)在聚氯乙烯(PVC)表面固定化,进一步对固定PEG后的PVC进行肝素化处理,以改善PVC材料的抗凝血性能。探讨了PEG浓度对Ar等离子体固定化反应效果的影响。通过X射线光电子能谱(XPS)、衰减全反射红外光谱(ATR-FTIR)、扫描电镜(SEM)和接触角测定研究了固定PEG前后PVC的表面性能和表面形貌的变化。XPS分析证实肝素已成功地共价键合于PVC表面。采用体外凝血时间测定和血小板粘附实验对材料的抗凝血性能进行评价,结果表明,被修饰PVC材料的抗凝血性能显著提高。     

聚乙烯的表面光接枝改性研究进展

综述了紫外光引发接枝改性聚乙烯表面的研究进展,包括光接枝聚合机理,改性方法,接枝链的结构和形态,影响因素等。     

抗凝血生物材料研究 Ⅵ. 聚乙烯的表面肝素化

通过聚乙烯膜表面的臭氧活化及其随后与甲基丙烯酸环氧丙酯（ＧＭＡ）的接枝共聚、α，ω 二氨基聚氧乙烯（ＪｅｆａｍｉｎｅＥＤ ６００、ＥＤ ９００、ＥＤ ２００１）的亲核开环反应以及在碳二亚胺（ＥＤＣ）缩合剂存在下与肝素的缩合反应，可对聚乙烯膜表面进行高效的肝素共价固定化，其中ＪｅｆａｍｉｎｅＥＤ ６００所固定的肝素浓度可高达１３６μｇ／ｃｍ２，材料抗凝血性也最好     

微波等离子体诱导聚乙烯表面接枝甲基丙烯酸甲酯

聚乙烯（ＰＥ）通常作为性能优良的薄膜材料被广泛使用,但由于其表面能低,导致表面亲水性差,粘结性弱,染色性能、印刷性能等很不理想［１,２］．在高分子材料的各种表面改性方法中,接枝共聚是一种很有效的途径［３～５］．本文探讨了用微波冷等离子体激活聚乙烯表面...     

高密度聚乙烯粉末的电子束辐射接枝

高密度聚乙烯粉末的电子束辐射接枝王勇，黄劲，李瑞海（成都科技大学纺织工学院，成都６１００６５）（成都科技大学高分子材料系６１００６５）关键词：ＨＤＰＥ粉末，电子束辐射，接枝聚合本文采用电子束予辐射法使聚乙烯粉末表面产生活性中心，然后通过液－固相接枝共...     

肝素化聚甲基丙烯酸的合成及抗凝血性能的研究

本工作采用四价铈盐作引发剂,进行了甲基丙烯酸在肝素上的接枝聚合,合成了肝素化的交联型聚甲基丙烯酸,并对接枝聚合的反应条件及接枝聚合物的抗凝血性能进行了研究.实验结果表明,肝素化的聚甲基丙烯酸具有优良的抗凝血性能,是一种很有应用前景的新型聚合物.     

聚乙烯与丙烯酸的溶液接枝聚合

以过氧化苯甲酰为引发剂，二甲苯为溶剂，进行了丙烯酸与低密度聚乙烯的溶液接枝聚合，研究了ＢＰＯ用量、溶液浓度以及丙烯酸用量对接枝率的影响。聚乙烯接枝了丙烯酸后与铝的粘结强度显著增大，当接枝率为７．２％时，剥离强度由未接枝时的１９３Ｎ／ｍ，提高到９８４Ｎ／ｍ。     

低密度聚乙烯的接枝改性

低密度聚乙烯的接枝改性;低密度聚乙烯;甲基丙烯酸缩水甘油酯;非等温结晶Avrami方程     

Surface modification of polyethylene fiber by graft polymerization

To improve the wettability and adhesion, graft polymerization of acrylamide (AAm) and glycidyl methacrylate (GMA) was performed onto the surface of ultra-high modulus polyethylene (UHMPE) fiber pretreated with Ar plasma. Following the plasma treatment and the subsequent exposure to air to introduce peroxides onto the fiber surface, graft polymerization onto the UHMPE fiber was allowed to proceed from the polymer peroxides either in deaerated monomer solution at an elevated temperature (degassing method), or in aerated monomer solution containing riboflavin at 30°C under UV irradiation (photoinduction method). The monomer solution was prepared from water and dioxane for AAm and GMA, respectively. After rigorous removal of homopolymers, surface analysis of the grafted fibers was performed with ATR-FTIR and XPS, which revealed that PAAm and PGMA chains were grafted in the surface region of fibers. The grafting rate of PAAm by the photoinduction method was much higher than that by the degassing method when compared at the same concentration of the AAm solution. The amount of PGMA grafted was greatly affected by UV irradiation time, but depended on plasma treatment time to an insignificant extent if the treatment was carried out for longer than 30 s. Reaction of propylamine with the PGMA-grafted surface resulted in the appearance of a nitrogen peak in the XPS spectrum, suggesting the presence of epoxy groups on the surface of PGMA grafted fiber. © 1994 John Wiley & Sons, Inc.     

Evidence and mechanisms of filling polymerization by plasma-induced graft polymerization

Using a plasma-induced graft polymerization technique, which is well known as a surface modification method, the grafted polymer was formed in pores of the porous material. This study examined the filling mechanism. Five thin porous films were sandwiched together, and employed as the substrate. The substrate was treated by plasma, and the change in surface tension and radical formation was measured for each sheet after the sheet was separated. The only surface on which surface-tension change was detected, was that of the sheet directly exposed to the plasma. Although plasma treatment made polymer radicals primarily on the outer surface of the sheet, the treatment also formed a few radicals inside the sheets. The radicals inside the sheets reacted with methylacrylate and grafted polymer formed in the pores. The location of grafted polymer depended on the balance between monomer diffusivity and reactivity. The grafting rate depended on which monomer solvent was used for the polymerization. Thus, the grafted membrane morphology could be controlled by varying the grating solvent composition. © 1996 John Wiley & Sons, Inc.     

Evaluation of antithrombogenicity of ion‐implanted silicone rubber

Ion implantations into silicone rods were performed at 150 keV with doses ranging from 1 × 10⁷ to 3 × 10¹⁷ ions/cm². The antithrombogenicity was tested by the superior vena cava (SVC) indwelling method for two days in rats with ¹¹¹In‐tropolone ‐ platelets, and by the inferior vena cava (IVC) indwelling method. Results of the SVC indwelling method showed that platelet accumulation on ion ‐ implanted specimens decreased. Macroscopic views of the ion‐implanted IVC specimens in dogs revealed little thrombus formation. In particular, SVC indwelling method revealed that O₂⁺, K⁺ and Kr⁺ (1 × 10¹⁷ ions/cm²) implantation was most effective in reducing platelet accumulation. Copyright © 1999 John Wiley & Sons, Ltd.     

Synthesis of functional polyethylene graft copolymers by nitroxide‐mediated living radical polymerization

This paper describes a new method to prepare graft copolymers, such as polyethylene‐g‐polystyrene (PE‐g‐PS), with a relatively well‐controlled reaction mechanism. The chemistry involves a transformation process from the metallocene copolymerization of ethylene and m,p‐methylstyrene (m,p‐MS) to nitroxide‐mediated “living” free radical polymerization (LRFP) of styrene. The metallocene catalysis produces ethylene‐co‐m,p‐methylstyrene (EMS) random copolymers. Next, 1‐hydroxyl‐2,2,6,6‐tetramethylpiperidine (HO‐TEMPO) was synthesized by the reduction of TEMPO with sodium ascorbate. The macroinitiator (EMS‐TEMPO) was synthesized with the bromination reaction of EMS, and the following nucleofilic reaction with this functional nitroxyl compound. The resulting macroinitiator (EMS‐TEMPO) for LRFP was then heated in the presence of styrene to form graft copolymer. DSC, ¹H‐NMR, FTIR spectroscopy were employed to investigate the structure of the polymers. The results of Molau test showed that PE‐g‐PS could be a potential good compatilizer. Copyright © 2008 John Wiley & Sons, Ltd.     

Surface graft polymerization of glycidyl methacrylate onto polyethylene and the adhesion with epoxy resin

Surface graft polymerization of glycidyl methacrylate (GMA) was carried out onto a high- density polyethylene (PE) sheet pretreated with corona to introduce peroxides onto the PE surface. Graft polymerization of GMA was effected by UV irradiation of the coronatreated PE in the presence of monomer solution without the use of any photosensitizer. The graft layer was found by staining the PE cross section to localize in the surface region of PE. The physical change in the PE surface was characterized by scanning electron microscopy, while the chemical changes due to the GMA graft polymerization were assessed by the dynamic contact angle, FT-IR, and x-ray photoelectron spectroscopy (XPS) measurement. The peroxide formation by corona exposure was confirmed by the XPS measurement after derivatization with SO₂. The epoxy groups introduced onto the PE surface by the GMA graft polymerization were reactive with water (in the presence of HCI) and amines. The adhesion between the GMA-grafted PE and an epoxy resin was studied by means of a shear strength test method. The GMA-grafted PE exhibited strong interfacial adhesion with the epoxy resin, compared to the original and corona-treated PE. The adhesion strength of the GMA-grafted PE was nearly two times higher than that of the corona-treated PE. This strongly suggests that the enhanced adhesion between the surface-grafted PE and the epoxy resin is ascribed to covalent bonding of the epoxy groups on the GMA-grafted surface to the amines in the epoxy resin. © 1995 John Wiley & Sons, Inc.     

Oxidation of polyethylene surface by corona discharge and the subsequent graft polymerization

Oxidation of a polyethylene (PE) surface by corona discharge and the subsequent graft polymerization of acrylamide (AAm) were studied. The maximum amount of peroxides introduced by corona treatment at a voltage of 15 kV was about 2.3 × 10^?9 mol cm^?2. The decomposition rate of peroxide and the dependence of graft amount on the storage period of the corona-treated PE films showed that there were several kinds of peroxides, the labile one being mainly responsible for the initiation of graft polymerization. When the corona-treated film was brought into contact with a deaerated aqueous solution of AAm, graft polymerization took place more strongly with the treatment time, but was reduced after passing a maximum. Although the x-ray photoelectron spectroscopic analyses of the corona-treated PE films showed homogeneous oxidation of the outer polymer surface by corona discharge, optical microscopy on the cross section of the grafted film revealed the graft polymerization to be limited to a very thin surface region.     

Novel surface fixation technology of hydrogel based on photochemical method: Heparin-immobilized hydrogelated surface

This article reports a novel photoinduced surface process technology enabling simultaneous hydrogel formation and its surface fixation on polymeric substrates. The process consists of layering two different types of photoreactive coatings on a polymeric surface, an azidophenyl-bearing polymer as an adhesive layer and cinnamoylated copolymer as a hydrogel layer, and subsequent UV irradiation. The photoreactive adhesive polymer coated on a substrate is poly(m-azidostyrene), in which photoreaction of phenyl azido groups is responsible for the chemical bonding between the substrate and hydrogel. N,N-dimethylacrylamide copolymer containing cinnamate moieties in their side chains, which undergo photocrosslinking via intermolecular dimerization, was applied as an overcoat on the adhesive layer. UV irradiation resulted in the formation of hydrogel chemically bonded onto the substrate. This was confirmed by ESCA measurements. A heparin-immobilized hydrogelated surface with controlled release characteristics was demonstrated. © 1993 John Wiley & Sons, Inc.     

Living radical graft polymerization of methyl methacrylate to polyethylene film with typical and reverse atom transfer radical polymerization

Nickel‐mediated atom transfer radical polymerization (ATRP) and iron‐mediated reverse ATRP were applied to the living radical graft polymerization of methyl methacrylate onto solid high‐density polyethylene (HDPE) films modified with 2,2,2‐tribromoethanol and benzophenone, respectively. The number‐average molecular weight (M_n) of the free poly(methyl methacrylate) (PMMA) produced simultaneously during grafting grew with the monomer conversion. The weight‐average molecular weight/number‐average molecular weight ratio (M_w/M_n) was small (<1.4), indicating a controlled polymerization. The grafting ratio showed a linear relation with M_n of the free PMMA for both reaction systems. With the same characteristics assumed for both free and graft PMMA, the grafting was controlled, and the increase in grafting ratio was ascribed to the growing chain length of the graft PMMA. In fact, M_n and M_w/M_n of the grafted PMMA chains cleaved from the polyethylene substrate were only slightly larger than those of the free PMMA chains, and this was confirmed in the system of nickel‐mediated ATRP. An appropriate period of UV preirradiation controlled the amount of initiation groups introduced to the HDPE film modified with benzophenone. The grafting ratio increased linearly with the preirradiation time. The graft polymerizations for both reaction systems proceeded in a controlled fashion. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3350–3359, 2002