Surface graft copolymerization of 2‐hydroxyethyl methacrylate onto low‐density polyethylene film through corona discharge in air

The corona discharge technique was explored as a means of forming chemically active sites on a low‐density polyethylene (LDPE) film surface. The active species thus prepared at atmospheric pressure in air was exploited to subsequently induce copolymerization of 2‐hydroxyethyl methacrylate (HEMA) onto LDPE film in aqueous solution. The results showed that with the corona discharge voltage, reaction temperature, and inhibitor concentration in the reaction solution the grafting degree increased to a maximum and then decreased. As the corona discharge time, reaction time, and HEMA concentration in the reaction solution increased, the grafting degree increased. With reaction conditions of a 5 vol % HEMA concentration, 50°C copolymerization temperature, and a 2.0‐h reaction time, the degree of grafting of the LDPE film reached a high value of 158.0 μg/cm² after treatment for 72 s with a 15‐kV voltage at 50 Hz. Some characteristic peaks of the grafted LDPE came into view at 1719 cm^?1 on attenuated total reflectance IR spectra (C?O in ester groups) and at 531 eV on electron spectroscopy for chemical analysis (ESCA) spectra (O_1s). The C_1s core level ESCA spectrum of HEMA‐grafted LDPE showed two strong peaks at ～286.6 eV (? C ? O? from hydroxyl groups and ester groups) and ～289.1 eV (O?C ? O? from ester groups), and the C atom ratio in the ? C? O? groups and O?C? O groups was 2:1. The hydrophilicity of the grafted LDPE film was remarkably improved compared to that of the ungrafted LDPE film. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2881–2887, 2001     

PE膜表面接枝间苯二酚

Low density polyethylene film surface-grafted process. Firstly, acrylic acid was grafted to the surface grafting. Secondly, the carboxylic groups in poly （acrylic resorcinol was prepared by a sequential of low density polyethylene by UV photoacid） chains were transferred to acyl chloride groups by the reaction of carboxylic groups with thionyl chloride. The stability of acyl chloride groups in several solvents （alcohol, water, acetone, aqueous NaOH and in N2 atmosphere） was investigated, and N2 atmosphere and acetone were appropriate media to protect acyl chloride groups from side reaction. Finally, resorcinol monomer reacted with acyl chloride to append to the poly（acrylic acid） chains at room temperature. FT-IR ATR was used to characterize the change of carbonyl groups during each step of the grafting process. Furthermore, by the experimental data of gravimetric analysis the grafted resorcinol monomer on the surface of low density polyethylene film was verified to have undergone condensation with acetone further in the resorcinol/acetone solution at 56℃, which might be a useful feature for synthesizing a thermoplastic/thermosetting composition.     

Graft copolymerization of 4-vinylpyridine and methyl acrylate onto polyethylene film by radiochemical method

Graft copolymerization of 4-vinyl pyridine (4-VP) and methyl acrylate (MA) onto polyethylene (PE) was studied in aqueous medium in air by the mutual irradiation method. The percentage of grafting was determined as a function of the (i) total dose, (ii) monomer concentration, and (iii) amount of water. The effect of different alcohols such as methanol, ethanol, isopropyl alcohol, butanol, and pentanol on the percentage of grafting of 4-VP and MA was studied. The effects of different amines on the percentage of grafting of 4-VP were also studied. The graft copolymers were characterized by IR spectroscopy and thermal analysis and by identifying the isolated polymer from the grafted film. Grafted PE film was tested for permeability behavior and was found to be permeable to a 0.5% aqueous sodium chloride solution. A plausible mechanism is suggested to explain the grafting of 4-VP and MA onto PE film. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 599–610, 1998     

高氯氯化聚乙烯对CR与MMA接枝共聚合的影响

以甲苯为溶剂,在９０℃条件下,研究了１０份氯含量为５７％的高氯氯化聚乙烯（ＨＣＰＥ）对１００份粘接型氯丁橡胶与７５份甲基丙烯酸甲酯（ＭＭＡ）接枝共聚合的影响。结果表明,该体系与无ＨＣＰＥ体系相比,ＭＭＡ转化率约提高４０％,产物接枝效率约高５０％,接枝度约高９０％。产物含有较高相对分子质量的级分,相对分子质量分布较宽,并且有较好的物理机械性能和较高粘接强度。     

Graft copolymerization of methyl methacrylate onto cellulosic biofibers

In this article, we have used the potassium persulfate to initiate the graft copolymerization of methyl methacrylate onto cellulosic biofibers in aqueous medium. Different reaction parameters, such as reaction time, initiator molar ratio, monomer concentration, amount of solvent, and reaction temperature, were optimized to get the maximum percentage of grafting (50.93%). The graft copolymers thus formed were characterized by Fourier transform infrared, scanning electron microscopy, X‐ray diffraction, and thermogravimetric, differential thermal analysis, and derivative thermogravimetric techniques. A mechanism is proposed to explain the generation of radicals and the initiation of graft copolymerization reactions. On grafting, percentage crystallinity decreases with reduction in its stiffness and hardness. The effect of grafting percentage on the physicochemical properties of raw as well as grafted fibers has also been investigated. The graft copolymers have been found to be more moisture resistant and also showed better chemical and thermal resistance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

The compatibility of poly(methyl methacrylate) and chlorinated polyethylene

The compatibility of poly(methyl methacrylate) with chlorinated polyethylene was studied using differential thermal analysis and dynamic mechanical measurements. For around 50% chlorination of polyethylene they were found to be compatible and show an LCST, but not at 27% chlorination as had previously been thought. The previous results were explained as due to a matching of refractive indices over some temperatures. The compatibility was explained by the heat of mixing which becomes favourable at chlorination levels above approximately 46%.     

聚乙二醇对直接合成聚乳酸-聚乙二醇的影响

为了得到综合性能较佳的生物降解材料聚乳酸-聚乙二醇(PLEG),以SnO为催化剂．直接以外消旋乳酸单体为原料,与不同数均分子量(Mn)的聚乙二醇(PEG)共聚合,通过直接熔融共聚法,在165℃、70Pa下．反应15h,合成了系列PLUG。用特性黏数测试、傅里叶变换红外光谱、核磁共振氢谱、差示扫描量热法、X射线衍射、接触角测试等手段对其进行表征,发现PEG的Mn为1000时,特性黏数最大,为0．4009dL/g,且亲水性得到改善。     

Graft polymerization of methyl methacrylate onto radiation‐peroxidized ultrahigh molecular weight polyethylene in the presence of metallic salt and acid

Using a radiation peroxide grafting technique, a ultrahigh molecular weight polyethylene (UHMWPE) stored at room temperature for 10 days after irradiation in air was graft copolymerized with methyl methacrylate (MMA) in the presence of metallic salt and acid. The MMA‐grafted UHMWPE samples were analyzed by measuring Fourier transform infrared spectroscopy in attenuated total reflectance (FTIR–ATR) and by electron spectroscopy for chemical analysis (ESCA). The 1,1‐diphenyl‐2‐picrylhydrzyl (DPPH) technique was utilized to evaluate the concentration of peroxide formed in the peroxidized UHMWPE samples by counting the quantity of DPPH consumed from the reaction of peroxide radicals with DPPH. It was shown that the inclusion of an FeSO₄ ·7H₂O and sulfuric acid in MMA grafting solutions was extremely beneficial and led to a most unusual synergistic effect in the radiation‐peroxidized grafting. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 659–666, 1999     

The grafting of methyl methacrylate onto ultrahigh molecular weight polyethylene fiber by plasma and UV treatment

In this study, ultrahigh molecular weight polyethylene (UHMWPE) fibers were treated with a gas plasma of argon for 5 min. The plasma-treated UHMWPE fibers were put into a methyl methacrylate solution with n-hexane or chloroform as the solvent and irradiated with a UV lamp. The UV irradiation time was changed. The surface topography that had a significant change on the fiber was seen by scanning electron microscopy. Infrared spectra (IR) and electron spectroscopy for chemical analysis (ESCA) were also studied to probe the surface atomic chemistry and to identify the functional groups and their relative changes with treatment conditions. The grafting content was estimated by the titration of esterfication method. It was found that the grafting amount for the system with chloroform as the solvent is larger than that for the system with n-hexane as the solvent. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:365–371, 1997     

Microwave irradiation graft copolymerization of hydroxyethyl methacrylate onto wool fabrics

Hydroxyethyl methacrylate was grafted onto woolen fabrics by microwave irradiation in the presence of catalyst (NH₄)₂S₂O₈. Various parameters of the graft copolymerization reaction, namely, time, microwave intensity, catalyst, and monomer concentration, were optimized. The graft copolymerization was also compared with conventional heating graft copolymerization at the same condition. Microwave irradiation was shown to improve the reactivity of the monomer. The moisture regain decreased as graft add-on increased. The Max load and the strain at Max load increased as graft add-on increased. The infrared spectra showed an additional peak at 1700 cm⁻¹, confirming ester carbonyl groups of the monomer. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2343–2347, 1998     

聚乙二醇及其衍生物催化合成苯并呋咱-N-氧化物的研究

研究了在聚乙二醇或其衍生物烷基聚氧乙烯醚、脂肪醇聚氧乙烯醚介质中,用NaOCl氧化邻硝基苯胺合成苯并呋咱-N-氧化物的反应过程,揭示了在合成反应中,聚乙二醇或其衍生物不仅可作为溶剂,还可替代碱金属氢氧化物,起到良好的催化作用。苯并呋咱-N-氧化物合成反应是以聚乙二醇或其衍生物为溶剂和催化剂,在邻硝基苯胺溶液中滴加理论用量1.1～1.5倍的次氯酸钠水溶液进行反应,合成温度为25～55 ℃,产物最高收率为98%。实验还表明,聚乙二醇及其衍生物稳定性好、次氯酸钠用量较小、反应温度适宜、时间短、条件缓和、产物收率和纯度高。     

Graft copolymerization of methyl methacrylate upon gelatin initiated by benzoyl peroxide in aqueous medium

The graft copolymerization of methyl methacrylate upon gelatin was studied using benzoyl peroxide as an organic initiator in aqueous medium. The grafting reactions were carried out within the 65–90°C temperature range, and the effect of monomer and initiator concentrations on the graft yield were also investigated. The maximum graft yield was obtained at a benzoyl peroxide concentration of 0.20 × 10⁻² mol/L and the optimum temperature was 80°C. Thermogravimetric analysis showed that the thermal stability of gelatin increased as a result of grafting. Further, such changes in the properties of methyl methacrylate‐grafted gelatin as density, moisture regain, and water uptake were also determined. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1547–1556, 1999     

羧甲基甲壳素接枝甲基丙烯酸甲酯的制备及成膜性

通过高速搅拌,未使用乳化剂,制备了羧甲基甲壳素和甲基丙烯酸甲酯的接枝共聚物,避免了产物中引入乳化剂杂质。利用红外光谱对接枝共聚物进行了表征。考察了不同接枝率的产物在12种常见溶剂中的溶解性,结果表明,不同接枝率的接枝共聚物都有良好的水溶性,可以形成无色透明的膜,扩大了其实际应用价值。     

Blood protein adsorption onto a polymeric biomaterial of polyethylene glycol and poly[(2‐hydroxyethyl methacrylate)‐co‐acrylonitrile] and evaluation of in vitro blood compatibility

A semi‐interpenetrating polymer network (semi‐IPN) of polyethylene glycol (PEG) and crosslinked poly[(2‐hydroxyethyl methacrylate)‐co‐acrylonitrile] was prepared and adsorption of bovine serum albumin (BSA) on the IPN surfaces was investigated. The dynamic nature of the adsorption process was studied, and the effects of various experimental factors such as pH and ionic strength on the adsorption isotherms of BSA were investigated. Various kinetic parameters, such as the adsorption coefficient, rate constant for adsorption and penetration rate constants, were calculated. For assessment of in vitro blood compatibility of the IPN surfaces, water sorption, blood clot formation tests and percent hemolysis measurements were performed. Copyright © 2004 Society of Chemical Industry     

聚双甲基丙烯酸聚乙二醇酯固-固相变储能材料的制备

制备了以聚甲基丙烯酸为骨架、聚乙二醇(PEG)为工作物质的新型高分子固-固相变储能材料。对PEG和几种不同的相变材料分别进行DSC测试,对PEG分子量为4000的相变材料进行非等温DSC测试。结果表明,与纯PEG相比,相变材料的相转变温度降低12.3℃,相变焓降低45 J/g。随着聚乙二醇分子量由2000依次增加为4000,6000,10000,相变材料的相转变温度分别为44.8,52.9,63.8和74.3℃,相变焓分别为142.9,203.2,190.1,231.4 J/g,均有增加的趋势。随着升温速率增加,PEG分子量为4000的PCM的相变温度依次升高,分别为47.4,50.0和53.1℃。     

Graft copolymerization studies. III. Methyl methacrylate onto polypropylene and polyethylene terephthalate

The tert‐butoxy radical‐facilitated grafting of methyl methacrylate (MMA) onto commercial polypropylene (PP) pellets and fiber was investigated in heterogeneous conditions similar to practical systems. Free‐radical grafting of several other monomers onto PP fiber was also investigated. Also, preliminary data from the grafting of MMA onto poly(ethylene terephthalate) pellets is presented. The PP‐graft‐PMMA residues were detected by solid‐state ¹³C‐NMR and photoacoustic IR spectroscopy. There was a good correlation between the degree of grafting (DG) determined from these spectroscopic techniques and the results from gravimetric methods. A maximum grafting efficiency of over 50% was found, whereas DG (20%) remained constant at various PP pellet, initiator, and monomer concentrations. However, at relatively low PP fiber concentrations, the DG was 27%; the increase was most likely due to the greater surface area of the fiber. There was also a reduction in DG (14%) at relatively low initiator concentrations. The reaction conditions were altered to favor grafting by the addition of more polymer substrate. When the ratio of tert‐butoxy radicals to PP was decreased, more of the substrate remained unmodified, and empirical calculations showed the formation of grafts with up to 40 monomer units. At high initiator concentrations, calculations showed that the graft residues were 1–2 units long. Therefore, variation of the polymer, initiator, and monomer concentrations was shown to have a significant effect on grafting. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 898–915, 2002     

Effect of ultrasonic irradiation on ceric‐salt‐initiated grafting of methyl methacrylate onto regenerated cellulose film

Effect of ultrasonic irradiation on ceric salt (Ce⁴⁺)‐initiated grafting of methyl methacrylate (MMA) on regenerated cellulose film (thickness = 20 μm) was investigated under an air atmosphere in water solvent at 60°C. The grafting system with the ultrasonic irradiation was characterized by higher percentage of grafting and graft efficiency than the system without the irradiation. Reaction of cellulose with Ce⁴⁺ was also accelerated by the ultrasonic irradiation. No accelerating effect of grafting due to the ultrasonic irradiation was observed for the system under reduced pressure of 5 torr. The effect of the ultrasonic irradiation on the average molecular weight of MMA‐grafted chains was also studied. Moreover, the surface layer of the resulting grafted films was examined by attenuated total reflection–infrared (ATR–IR) measurement and scanning electron microscopy (SEM) observation. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 251–258, 1999     

Graft copolymerization of itaconic acid onto chitin and its properties

Modification of chitin by grafting with itaconic acid (IA) was carried out using potassium persulfate as redox initiator. In complimentary experiments, grafting was performed using γ‐radiation. Grafting was confirmed by FTIR spectroscopy. The effect of monomer concentration, initiator concentration and copolymerization temperature on the percentage of grafting were studied. The effect of radiation dose was also investigated. Values for percentages of grafting of up to 300 % were reached. It was observed that the percentage of grafting increased with increasing monomer concentration and showed a tendency to level off at IA concentration of 0.1 mol l^?1. The percentage of grafting increased with temperature up to 60 °C and then decreased. The solubility of the grafted chitin was studied in organic and inorganic solvents. The complexation of the grafted chitin with some cations, namely copper, nickel, cobalt, zinc and lead, was also investigated. The metal uptake was measured by UV spectroscopy. Thermogravimetric analysis of the grafted chitin was also studied. Copyright © 2004 Society of Chemical Industry     

Graft copolymerization of hydroxyethyl methacrylate onto chitosan

Chitosan is a polysaccharide derived from chitin, which is commonly found in shellfish waste materials. The present work is concerned with the graft copolymerization of 2-hydroxyethylmethacrylate (HEMA) onto chitosan using thiocarbonation–potassium bromate for redox initiation. The combined effects of the principal reaction variables for the grafting reaction were studied systematically. This grafting reaction was studied with respect to percentages of graft yield (%G.Y.), homopolymer (%H.P.), and total conversion (%T.C.). A tentative polymerization mechanism is proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 683–702, 2001     

Graft polymerization of methyl methacrylate onto polyvinyl alcohol using Ce4+ initiator

Methyl methacrylate (MMA) was graft polymerized onto polyvinyl alcohol (PVA) using ceric ammonium sulfate as an initiator in aqueous medium. The grafting efficiency of MMA was studied as a function of monomer and initiator concentration, time, pH, and temperature. Grafting efficiency was found to be optimum at a particular level of ceric ammonium sulfate (3.16 × 10⁻³ mol L⁻¹), PVA (1.0 g L⁻¹), MMA (0.469 mol L⁻¹), H₂SO₄ (0.188 mol L⁻¹), temperature (45°C), and time (4 h). The probable reasons for the influence of reaction variable on the observed trend of MMA towards grafting have been discussed. Acid hydrolysis and infrared spectroscopy were used for the confirmation of graft copolymer formation. Thermogravimetric analysis of PVA and a representative graft copolymer were studied. The solubility/swellability and the gelatinization characteristics are also reported. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 523–527, 1998