ABS／SMA及ABS／SMA／PMMA的性能研究

研究了ABS／SMA和ABS／SMA／PMMA共混体系,确定了配比与合金的拉伸强度、冲击强度、断裂伸长率、模量、热变形温度、熔体流动速率等关系。结果表明：①ABS中引入SMA可以显著提高耐热性能,但同时合金的缺口冲击强度严重降低;②ABS中引入SMA可使合金的流动性能提高;③ABS／SMA体系中引入第三组分PMMA可以大幅度提高共混物的缺口冲击强度,同时使合金的耐热性能有所提高。     

HDPE／LDPE混合物熔融接枝GMA的研究

采用熔融接枝的方法,制备了(HDPE/LDPE)-g-GMA（甲基丙烯酸缩水甘油酯）接枝吻,研究了引发剂的用量、GMA的用量、苯乙烯（St)/GMA的配化、转速、反应时间等因素对接枝率的影响。确立了最佳的接枝配方和工艺条件：过氧化二异丙苯（CDP）用量0.1份、GMA用量3份、St用量3份、温度180℃、转速60r/min、反应时间为10min。接枝反应动力学曲线与接枝反应过程的机理特征相吻合。红外光谱的分析结果表明GMA确实接到了大分子链上;DTA分析结果表明,接枝物中GMA的引入导致大分子链的规整性降低,熔融温度略有下降。     

Grafting vinyl monomers onto silk (Bombyx mori) using different initiators: Properties of grafted silk

The graft–copolymerization of silk with methacrylamide (MAA), 2‐hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA) was studied using three different free‐radical initiators: an inorganic peroxide [ammonium persulfate (APS)] and two azo compounds [2,2′‐azobisisobutyronitrile (AIBN) and 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (ADC)]. The rate and yield of grafting followed the order: APS > AIBN > ADC. The performance of AIBN was close to that of APS in terms of weight gain attained. The degree of yellowing of grafted silk varied as a function of the initiator–monomer system used. APS induced the highest degree of yellowing, regardless of which monomer was used, whereas silk grafted with the MAA/AIBN system displayed the lowest level of yellowing. Moisture regain of grafted silk changed as a function of the hydrophilic/hydrophobic character of the grafted polymer, regardless of the kind of initiator used. Accordingly, tensile properties showed a tendency to decrease with increasing weight gain of grafted silk, the extent of which was independent of the kind of monomer and initiator used. The different initiators did not induce any appreciable change in the fine structure of silk, as demonstrated by optical measurements. Uneven surface deposition of homopolymer was detected to variable extent with MMA and HEMA grafting, whereas the surface of MAA‐grafted silk was completely free of any foreign deposit, independently of the initiator used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1401–1409, 2001     

Hydrophobic cellulose fibers via ATRP and their performance in the removal of pyrene from water

In the present work, cellulose fibers were modified by grafting with poly(lauryl acrylate) and poly(octadecyl acrylate). The grafted materials were prepared by polymerization of the corresponding monomers via surface initiated atom transfer radical polymerization, starting from cellulose papers previously modified with 2‐bromoisobutyryl groups. The polymerizations were carried out in the presence of ethyl‐2‐bromoisobutyrate, as a sacrificial initiator, added to control the molecular weight of the anchored segments, and polymerization kinetics. The grafting of both polymers was confirmed by infrared spectroscopy and elemental analysis. The effect of grafting these polymers on the thermal stability, morphology, and surface properties of cellulose fibers was studied using thermogravimetric analysis, scanning electron microscopy, and measuring water contact angle, respectively. The results reveal that grafting poly(lauryl acrylate) and poly(octadecyl acrylate) to cellulose confers the filter paper a hydrophobic character, and increases its affinity with pyrene, allowing the removal of this pollutant from water. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44482.     

Physical and Morphological Properties of Combined Treated Wood Polymer Composites by Maleic Anhydride and Methyl Methacrylate

Wood polymer composites were prepared by consecutive impregnation with maleic anhydride (MAN) and methyl methacrylate (MMA). Samples impregnated with MAN alone, were heated at 120°C and 150°C for 4 and 8 h. Based on the Fourier transform infrared (FT-IR) analysis and soaking-drying test results, treatment with MAN at 150°C for 4 h resulted in formation of stable crosslinks. In the second stage, MMA was used for in situ polymerization within MAN-treated wood. Field emission scanning electron microscopy observation and FT-IR analysis indicated that MMA copolymerized with MAN, and the resultant polymer filled up the lumen and is also grafted on to the cell wall. Improvement of water repellency and dimensional stability were observed in the treated samples, particularly in combined treated samples. The MAN/MMA treatment improved interaction between polymer and wood.     

All-organic Poly(butyl methacrylate)/Poly(vinylidenefluoride-trifluoroethylene) Dielectric Composites with Higher Permittivity and Low Dielectric Loss for Energy Storage Application

With the rapid development of electronic industry and technology, there are increasingly stringent requirements on dielectric materials with higher permittivity, lower loss, and enhanced breakdown field. Since single dielectric material cannot meet the demands of industrialization, polymer-based dielectric materials with better quality have been widely applied. This study focused on a poly(butyl methacrylate/poly(vinylidene fluoride-trifluoroethylene) dielectric composite thin film, which were prepared by solution casting method. X-ray diffraction and differential scanning calorimetry data indicated that introducing poly(butyl methacrylate) led to increase in the crystallinity. The result of scanning electron microscopy showed the good compatibility between poly(vinylidene fluoride-trifluoroethylene) and poly(butyl methacrylate). Besides, the dielectric film remained good mechanical property. The dielectric properties were studied as a function of filler content and frequency. The results showed that the permittivity was as high as 13.3, while the breakdown field was 322?MV m^?1 when the fraction of poly(butyl methacrylate) was 10%. Blending poly(butyl methacrylate) improved the dielectric performance of the poly(vinylidene fluoride-trifluoroethylene).     

State-of-the-Art Overview on Polymer/POSS Nanocomposite

Research into polymer containing polyhedral oligomeric silsesquioxane has been expanded during the past years, enlightening new categories of polymer/polyhedral oligomeric silsesquioxane nanocomposite and unanticipated applications. These hybrids own superior structural and functional properties (strength, thermal stability, optical features, low toxicity, biocompatibility) due to nanometer size of polyhedral oligomeric silsesquioxane. The state of polyhedral oligomeric silsesquioxane-reinforced polymeric [poly(methyl methacrylate, poly(vinyl chloride), polyurethane, polyamide, epoxy, and poly(ethylene glycol)] systems are reviewed in this article. Physical blending, covalent bonding, and chemical cross-linking have been used to provide excellent reinforcement. A comprehensive coverage of various appliances of polymer/polyhedral oligomeric silsesquioxane nanocomposite has been given particularly aerospace, semiconducting material, biomedical, and textile industry.     

Concentration effects in the base-catalyzed hydrolysis of oligo(ethylene glycol)- and amine-containing methacrylic monomers

Concentration effects in the base-catalyzed hydrolysis of water-soluble methacrylates (3-(N,N-dimethylaminoethyl) methacrylate (DMAEMA), 2-hydroxyethyl methacrylate (HEMA) and oligo(ethylene glycol) methacrylates (OEGMAs)) have been studied. These monomers are rapidly hydrolyzed in the presence of bases at the room temperature in dilute aqueous solutions, but the reaction rate decreases sharply in highly concentrated solutions. A clear correlation was found between a form of the viscosity isotherm for DMAEMA solutions and the concentration dependence of the autocatalytic hydrolysis rate which indicates the connection of process kinetics with the structure of solutions. These data should be considered when carrying out homo- and copolymerization of the previously mentioned monomers in aqueous solutions.     

A new initiating system based on [(SiMes)Ru(PPh3)(Ind)Cl2] combined with azo-bis-isobutyronitrile in the polymerization and copolymerization of styrene and methyl methacrylate

The homopolymerization and copolymerization of styrene and methyl methacrylate, initiated for the first time by the combination of azo-bis-isobutyronitrile (AIBN) with [(SiMes)Ru(PPh₃)(Ind)Cl₂] complex. The reactions were successfully carried out, on a large scale, in presence this complex at 80 °C. It was concluded from the data obtained that the association of AIBN with the ruthenium complex reduces considerably the transfer reactions and leads to the controlled radical polymerization and the well-defined polymers.     

PE-LLD-g-(GMA-co-St)的反应挤出及应用

采用反应挤出方法,制备了甲基丙烯酸缩水甘油酯(GMA)和苯乙烯(St)接枝改性的线型低密度聚乙烯(PE-LLD)产品[PE-LLD-g-(GMA-co-St)]。研究了St用量和反应时间对PE-LLD-g-(GMA-co-St)接枝率和熔体流动速率(MFR)的影响。结果表明,当St与GMA质量比为5︰9,反应时间为120 s时,所制备试样接枝率达到1.69%,MFR(190℃,2.16 kg)达0.69 g/10 min。将制备的PE-LLD-g-(GMA-co-St)和PE-LLD-g-MAH作为相容剂应用于聚乙烯无卤阻燃电缆料,对比了水煮老化前后的拉伸性能。结果表明,与PE-LLD-g-MAH为相容剂的电缆料试样相比,以PE-LLD-g-(GMA-co-St)为相容剂的电缆料试样虽然拉伸强度较低,但具有较高的断裂伸长率和较高的耐水煮老化性能,其拉伸强度和断裂伸长率分别为13.9 MPa和231%,水煮10 h后的保留率分别为84.9%和85.7%,满足电缆行业应用标准要求。