官能化聚烯烃的进展和应用

官能化聚烯烃是由聚烯烃改性后得到的产物,一般通过交联改性、共聚改性、固相力化学改性和接枝改性等方法制备,可应用于黏附、能源和封装等多重领域。基于聚烯烃高通量低成本的优势,聚烯烃接枝改性利用自由基反应直接向聚烯烃链上引入极性单体,较为经济便捷。聚烯烃接枝改性按反应条件的不同,又可分为溶液接枝、熔融接枝、辐射接枝、固相接枝和悬浮接枝。在接枝改性过程中,接枝率和接枝效率受多种因素影响,如聚烯烃型号、接枝单体、引发剂、共单体和反应条件等。本文综述了聚烯烃接枝改性不同接枝方法的研究进展,分析了各种接枝方法的优势和短板,并将接枝改性过程中的影响因素进行了总结。文章依据聚烯烃的可控自由基接枝改性和金属催化改性以及官能化聚烯烃的应用,展望了聚烯烃可控改性和官能化聚烯烃规模化生产。     

甲基丙烯酸缩水甘油酯接枝聚烯烃及在塑料改性中的应用进展

简单介绍了甲基丙烯酸缩水甘油酯熔融接枝聚烯烃的第二单体、引发剂、反应温度和反应时间等因素对接枝反应的影响,探讨了接枝率的测定方法及接枝聚烯烃在塑料改性中的应用等。     

反应挤出制备GMA接枝聚烯烃研究进展

介绍了化学滴定法和红外光谱分析2种表征甲基丙烯酸缩水甘油酯(GMA)接枝聚烯烃接枝率的方法,分析了GMA熔融接枝聚烯烃的反应机理,从反应挤出接枝物的影响因素、性能变化及其应用等方面介绍了反应挤出制备GMA接枝聚烯烃的最新进展.     

聚烯烃功能化进展

重点介绍了聚烯烃功能化常用的方法——氯化反应、磺化反应和聚烯烃与马来酸酐反应。聚烯烃与马来酸酐反应有3种方法(即溶液接枝、熔融接枝和固相接枝),其中,溶液接枝成本高,污染大,应用范围较小：熔融接枝是当今主要采用的方法,共单体的选择和多单体接枝的反应机理是其研究的重点;固相接枝法主要为粉末接枝,是一种有待进一步研究的新方法。     

聚烯烃接枝改性功能化的研究进展

综述了聚烯烃本体接枝改性和表面接枝改性在近两年来的研究进展 ,主要体现在接枝方法的优化、接枝物的扩充、接枝机理及反应动力学的研究以及接枝反应的控制、接枝物的高分子设计等方面     

聚烯烃接枝的研究进展

介绍了以过氧化物为中间产物的聚烯烃本体接枝、链转移反应、多单体熔融接枝的进展情况,重点阐述了表面接枝中的化学方法、利用辐照和光照技术对聚烯烃的表面改性、等离子体工艺及相关的聚丙烯表面改性剂。聚烯烃接枝是制备功能性聚烯烃的主要方法,也是高分子与工程材料领域最活跃的研究热点之一。     

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。     

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。     

聚烯烃表面改性对润湿性影响的研究进展

表面改性能有效提高聚烯烃的表面润湿性,从而扩大聚烯烃的应用领域。本文介绍了近几年国内外通过等离子体处理、表面光接枝、辐射接枝、化学接枝、等离子体接枝等方法对聚烯烃表面润湿性改性的研究进展。并介绍了各种改性对聚烯烃润湿性的影响。     

最新专利文摘

<正>具有长支链烯烃接枝复合物本发明涉及一种黏合剂复合物,该复合物由接枝复合物复合一种基础树脂组成。基础树脂可由线性低密度聚乙烯(LLDPE)和具有支长链聚乙烯组成,或由低密度聚乙烯(LDPE)和一种或多种添加剂组成。接枝复合物可以由一种接枝聚烯烃、烯烃弹性体和(或)活性反应产物构成的共混物,或由接枝聚烯烃和一种聚烯烃弹性体     

Autoadhesion of high density polyethylene (HDPE) to HDPE by ultraviolet grafting of methacrylates and acrylates

A study has been made on the effect of the presence of grafted acrylic layers on the autoadhesion of polyethylene. Methyl methacrylate (MMA), ethyl methacrylate (EMA), methyl acrylate (MA), ethyl acrylate (EA), and butyl methacrylate (BMA) were grafted onto high density polyethylene (HDPE). The grafting reaction was faster at higher temperature and methacrylates graft more easily than acrylates. For methacrylates and acrylates, the grafted amount increases with increasing length of the pendant alkyl chain. The grafting temperature is a crucial factor affecting the adhesion of grafted PE samples. For the samples grafted at lower temperature (in a room temperature water bath), the adhesion is very low (less than 50 N/m), even for very thick grafted layers. But for the samples grafted at higher temperature, much higher adhesion can be obtained. The presence of homopolymer was another factor affecting the adhesion of PE samples. When homopolymer is removed from the surface of the grafted sample, higher adhesion can be obtained. For some samples, the highest peel strength of more than 1000 N/m has been obtained. The low adhesion of the samples grafted at low temperature is attributed to the high branching of grafted chains.     

Hydrophilic and adhesive properties of methacrylic acid-grafted polyethylene plates

Methacrylic acid (MAA) was grafted onto polyethylene (PE) surfaces by simultaneous irradiation with UV rays in the liquid phase to estimate hydrophilic and mechanical properties for MAA-grafted PE plates. The amount of grafted MAA increased sigmoidally with UV irradiation time, and the higher grafted amount was obtained at higher monomer concentrations. With an increase in grafting of MAA, the wettabilities from the contact angles of water were enhanced and the refractive indices from the ellipsometry decreased. Though the contact angles remained constant above the grafted amount of 0.02 mmol/cm², the refractive indices approached the value of PMAA around 0.009 mmol/cm², indicating that the PE surfaces were fully covered with grafted PMAA chains. Then, at a fixed grafted amount, the grafted layer can absorb more water and the grafted PE plates possessed higher tensile shear adhesive strength, in case grafting was carried out at lower monomer concentrations. Surface properties depended on the density of carboxyl group at the surfaces of grafted layers, whereas adhesive properties depended on the structural properties of grafted chains as well as on the density of carboxyl group of the whole grafted layers.     

聚乙烯反应挤出接枝马来酸酐的研究

以过氧化二异丙苯(DCP)为引发剂,使用反应挤出机研究了不同种类聚乙烯及其共混物接枝马来酸酐的反应规律。实验结果表明:产物的接枝率和熔体流动速率(MFR)变化与聚乙烯的种类有直接关系,接枝性能从优到差的顺序为:LDPE>LLDPE>HDPE;引发剂DCP对LDPE接枝产物的MFR影响显著,对LLDPE次之,对HDPE的MFR几乎没有影响;聚乙烯共混物的接枝性能取决于组成共混物的聚乙烯种类和用量。接枝产物及纯化后样品的红外光谱分析表明,酐基是以化学键连接到聚乙烯分子链上,接枝产物几乎不含游离态的马来酸酐。     

Effect of hydroquinone on location of methacrylic acid-grafted chains introduced into polyethylene film by photografting

Effect of hydroquinone (HQ) on photografting of methacrylic acid (MAA) on low-density polyethylene film (thickness = 30 μm) sensitized with xanthone was investigated at 60°C in water medium. Both the formation of grafted polymer and homopolymer were retarded by HQ. The contact angle of water on the MAA-grafted polyethylene films (sample with HQ) prepared in the system with HQ was larger than that of the grafted films (sample without HQ) prepared in the system without HQ. Based on electron probe microanalysis of the grafted films, it was found that distribution of grafted chains in the direction of film thickness is different between the both grafted films. Namely, the grafted chains of the sample with HQ distributed in the inside of the film compared with those of the sample without HQ. The difference in the distribution of grafted chains between the grafting systems with and without HQ was discussed in terms of effect of HQ on the photodecomposition of MAA-grafted chains and the subsequent initiation of polymerization by radicals due to the photodecomposition.     

接枝改性纳米氧化铝填充PTFE复合材料摩擦学性能研究

合成了含氟分子链接枝改性纳米氧化铝(Al2O3),用接枝改性纳米Al2O3填充聚四氟乙烯(PTFE),采用模压成型法制备了不同接枝改性纳米Al2O3含量的PTFE/纳米Al2O3复合材料;在摩擦磨损试验机上考察了接枝改性纳米Al2O3对PTFE/纳米Al2O3复合材料摩擦学性能的影响,利用扫描电子显微镜对复合材料的磨损表面进行了微观分析。结果表明,接枝改性纳米Al2O3填充PTFE复合材料在保持PTFE低摩擦系数的同时,提高了其耐磨损性能。     

Physical,chemical, and dyeing properties of Bombyx mori silks grafted by 2‐hydroxyethyl methacrylate and methyl methacrylate

To obtain silk weight gain and to improve silk properties, Bombyx mori silks were grafted with either 2‐hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA). The moisture regain of the HEMA‐grafted and MMA‐grafted silks depended on the hydrophilicity of the used monomers. The acid and alkaline resistances of the HEMA‐grafted and MMA‐grafted silks were clearly improved. Both commercial synthetic dyes, that is, acid and reactive dyes, and a natural dye extracted from turmeric, with potassium aluminum sulfate as a mordant, were used in this study. The results suggested that the dye uptake increased in the presence of poly(2‐hydroxyethyl methacrylate) or poly(methyl methacrylate) in the silk fibroin structures when acid and curcumin dyes were used. The washfastness level of the HEMA‐grafted silk dyed by acid and reactive dyes was similar to that of the degummed silk. However, the colorfastness to washing of the MMA‐grafted silk dyed by an acid dye was improved when the polymer add‐on concentration was 65%. In addition, the washfastness for both grafted silks was improved when they were dyed with natural curcumin dyestuff. The acid and alkaline perspiration fastness properties remained unchanged for the HEMA‐grafted and MMA‐grafted silks when acid, reactive, and curcumin dyes were applied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Estimation of surface properties of grafted layers formed on low- and high-density polyethylene plates by photografting of methacrylic acid and acrylic acid at different monomer concentrations and temperatures

An investigation was carried out on estimation of hydrophilicity, wettability and water-absorptivity, and surface analysis by X-ray photoelectron spectroscopy of the low- and high-density polyethylene (LDPE and HDPE) plates photografted with methacrylic acid (MAA) and acrylic acid (AA) at different monomer concentrations or temperatures. Wettability of the MAA-grafted LDPE and HDPE plates increased with grafted amounts, and became constant when the substrate surfaces were fully covered with the grafted polymer chains. On the other hand, for the AA-grafted LDPE and HDPE plates, wettability had the maximum value, and then gradually decreased against the grafted amount probably due to aggregation of grafted PAA chains, although the surfaces were covered with grafted PAA chains at lower grafted amounts compared with grafted PMAA chains. Water-absorptivity sharply increased at lower grafted amounts due to formation of shorter grafted polymer chains for photografting at lower monomer concentrations or due to restriction of the location of grafting to the outer surface region for photografting at lower temperatures. Therefore, for photograftings of AA or onto the HDPE plates, the substrate surfaces were covered with grafted polymer chains and the grafted layers formed possessed higher water-absorptivity at lower grafted amounts. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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。     

AUTOADHESION OF HIGH DENSITY POLYETHYLENE (HDPE) TO HDPE BY ULTRAVIOLET GRAFTING OF METHACRYLATES AND ACRYLATES

A study has been made on the effect of the presence of grafted acrylic layers on the autoadhesion of polyethylene. Methyl methacrylate (MMA), ethyl methacrylate (EMA), methyl acrylate (MA), ethyl acrylate (EA), and butyl methacrylate (BMA) were grafted onto high density polyethylene (HDPE). The grafting reaction was faster at higher temperature and methacrylates graft more easily than acrylates. For methacrylates and acrylates, the grafted amount increases with increasing length of the pendant alkyl chain. The grafting temperature is a crucial factor affecting the adhesion of grafted PE samples. For the samples grafted at lower temperature (in a room temperature water bath), the adhesion is very low (less than 50 N/m), even for very thick grafted layers. But for the samples grafted at higher temperature, much higher adhesion can be obtained. The presence of homopolymer was another factor affecting the adhesion of PE samples. When homopolymer is removed from the surface of the grafted sample, higher adhesion can be obtained. For some samples, the highest peel strength of more than 1000 N/m has been obtained. The low adhesion of the samples grafted at low temperature is attributed to the high branching of grafted chains.     

Effect of initiating groups introduced onto ultrafine silica on the molecular weight polystyrene grafted onto the surface

Summary The effect of initiating groups introduced onto silica surface on the molecular weight of grafted polystyrene chain was investigated. By the treatment of polystyrene-grafted silica with aqueous solution of alkali, surface grafted polystyrene was isolated from the surface. The molecular weight of polystyrene grafted onto the silica obtained from the radical graft polymerization initiated by peroxyester groups introduced onto the surface was found to be much larger than that from the cationic polymerization initiated by acylium perchlorate groups. The number of grafted polystyrene in the radical polymerization, however, was much less than that in the cationic polymerization. Furthermore, the effect of molecular weight of grafted polystyrene on the dispersibility of silica in tetrahydrofuran was examined.