Synthesis and photodegradable properties of methyl vinyl ketone–EPDM–styrene graft terpolymer

The graft terpolymerization of methyl vinyl ketone (MVK) and styrene (St) onto ethylene–propylene–diene terpolymer (EPDM) was carried out under various polymerization conditions. The synthesized graft terpolymer, MVK–EPDM–St (MVES), was identified by infrared (IR) spectroscopy. The effects of monomer concentration, mole ratio of MVK to St, reaction time, reaction temperature, and initiator concentration on the graft terpolymerization were examined. Upon UV irradiation in the presence of oxygen, the MVES-containing carbonyl group showed photodegradable properties caused by Norrish type II reaction. The new IR characteristic peaks, such as carbonyl, vinyl, and hydroxy groups of the photodegraded MVES, increased with increasing UV irradiation time. The tensile strength and elongation at break of MVES after UV irradiation were lower than those of before UV irradiation. The color difference of the irradiated MVES was higher than that of EPDM. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1721–1727, 1998     

UV‐radiation–induced preirradiation grafting of methyl methacrylate onto lignocellulose fiber in an aqueous medium and characterization

The preirradiation method of grafting has been established by ultraviolet radiation. Methyl methacrylate (MMA) was grafted onto jute fiber in an aqueous medium. The variation of graft weight with UV‐radiation time, monomer concentration, and reaction time was investigated. The conversion of monomer into homopolymer and graft copolymer was evaluated. The graft weight passes through a maximum value (～ 122%) with UV‐radiation time. The optimum value of the monomer concentration was evaluated for maximum degree of grafting. Graft copolymerization of MMA onto lignocellulose fiber significantly increases the elongation at break (～ 65%) compared to that of the “as‐received” sample. However, a linear decrease on breaking load was observed with the increase of graft weight. The estimation of degree of grafting was achieved using an IR technique by correlating band intensities with the degree of grafting. Considering the water‐absorption property, the grafted sample showed a maximum up to 61% decrease in hydrophilicity compared to that of the as‐received sample. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1667–1675, 2004     

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     

Grafting vinyl monomers onto wool fibers. VIII. Graft copolymerization of methyl methacrylate onto wool using peroxydiphosphate–fructose redox system

The graft copolymerization of methyl methacrylate onto wool fibers was investigated in aqueous solution using the peroxydiphosphate–fructose redox system. The rate of grafting was determined by varying monomer, acidity of the medium, temperature, nature of wool, and reaction medium. The graft yield increases with increase in peroxydiphosphate concentration. With increase in concentration of fructose up to 7.5 × 10^?4 mole/l., there is a significant increase in graft yield; and with further increase in concentration of fructose the graft yield decreases. The graft yield increases with increase in monomer concentration up to 65.72 × 10^?2 mole/l. and decreases thereafter. The grafting is considerably influenced by chemical modification prior to grafting. The effect of acid, temperature, and solvent on the rate of grafting has been investigated and a suitable rate expression has been derived.     

Graft polymerization of vinyl acetate onto starch. Saponification to starch–g–poly(vinyl alcohol)

Graft polymerizations of vinyl acetate onto granular corn starch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinylacetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. However, over half of the polymer was present as ungrafted poly-(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficiency. However, grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate-methyl methacrylate was carried out near 0°C, although conversion of monomers to polymer was low and grafted polymer contained 40-50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch–g–poly(vinyl acetate) to starch–g–poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch–g–poly(vinyl alcohol) in hot water was less than 50%; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized starch for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch–g–poly(vinyl acetate) with about 35% add-on, and a grafting efficiency of about 40% was obtained. A film cast from a starch–g–poly(vinyl alcohol) copolymer in which homopolymer was not removed exhibited a higher ultimate tensile strength than a comparable physical mixture of starch and poly(vinyl alcohol).     

The effect of grafted TMPM on the radiation resistance of polypropylene

The γ‐radiation–induced graft copolymerization of 2,2,6,6‐tetramethyl‐4‐piperidinyl methacrylate (TMPM) onto polypropylene (PP) was investigated using a simultaneous‐irradiation technique. The effects of solvents, atmospheres, dose, and monomer concentration on the percent of grafting were studied. The grafted TMPM showed better thermal stability, solvent extraction resistance, and compatibility with PP than monomeric TMPM or polymeric PTMPM. The stabilizing effectiveness of grafted TMPM on the radiation resistance of PP was found to be better than that of monomeric TMPM. The combination of grafted TMPM and low molecular weight hindered amine light stabilizers showed higher stabilizing effectiveness. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2150–2157, 1999     

Temperature-responsive permeability of porous PNIPAAm-g-PE membranes

Grafting a temperature-responsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), onto porous polyethylene (PE) membranes by UV irradiation was investigated. A wide range of graft yields (5–449%) was achieved by varying irradiation time (20–240 min) and monomer concentration (1.2–3.6 wt %). Characterization by XPS and SEM shows that the graft polymers are located both on the external surfaces as well as inside the pores of the membranes. Diffusional permeation experiments show that two distinct types of temperature responses were observed, depending on the graft yield; permeability increases with temperature in low graft yield membranes, while permeability decreases with temperature in high graft yield membranes. A mechanism explaining the dual valve functions of the graft membrane is proposed based on the location of the graft polymers on the membrane. It was also observed the permeability response exhibits a maximum with permeant molecular weight. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2133–2142, 1998     

马来酸酐在炭黑表面接枝聚合的研究

研究了过氧化苯甲酰引发马来酸酐在炭黑表面的接枝聚合反应，探讨了反应时间、引发剂用量、接枝单体用量对接枝率的影响。结果表明，接枝率随反应时间的延长而增加，但２ｈ后，接枝率增加不多；随引发剂用量的增加，接枝率呈上升趋势，但用量在１５ｍｇ以后，接枝率趋于定值；随接枝单体用量的增加，接枝率直线上升。在本实验条件下，接枝率达到９％。通过接枝产物的Ｘ射线光电子能谱及红外分析可以证实，马来酸酐已接枝到炭黑表面。从光学显微图像分析结果可知，马来酸酐接枝改性对炭黑在聚合物基体中的分布和分散性能起到良好的改善作用。     

Gamma preirradiation and grafting of 2N-morpholino ethyl methacrylate onto polypropylene fabric

The radiation-induced grafting of 2N-morpholino ethyl methacrylate (MEMA) in aqueous solution onto polypropylene fabric by a preirradiation technique has been investigated. Among the most important factors affecting the graft yield are monomer concentration, irradiation dose, reaction temperature, and time. It was found that the graft yield increased with increasing monomer concentration, grafting temperature, and preirradiation dose. The kinetic studies showed that the dependence of the grafting rate on monomer concentration is of 1.1 order. Moreover, the calculated overall activation energy was 14.2 kcal/mol. The grafted PP fabric shows an increase in moisture regain with increasing graft yield. Also, the dyeability with acid dye was significantly increased due to grafting with MEMA. © 1995 John Wiley & Sons, Inc.     

Adhesion studies of tyre cords with rubber. I. Synthesis and characterization of natural rubber graft copolymers

Glycidyl methacrylate and N-vinyl pyrrolidone have been grafted onto natural rubber at 32°C using the simultaneous cobalt-60 irradiation technique. The natural rubber samples were swollen in the monomers for 24 h and thereafter subjected to gamma irradiation. The homopolymers formed in the graft copolymerization reactions and unreacted monomer were removed by solvent extraction using acetone and methanol for glycidyl methacrylate and N-vinyl pyrrolidone monomer, respectively. The influence of total dose and monomer concentration on the graft parameters was investigated. The dependence of the rate of grafting on the monomer concentration was found to be 0.93 and 0.80 for glycidyl methacrylate and N-vinyl pyrrolidone, respectively. DSC and TGA studies of the polymers were undertaken. Grafted copolymers based on glycidyl methacrylate were relatively less thermally stable compared with ungrafted natural rubber.     

Grafting vinyl monomers onto silk fibers III. Graft copolymerization of methyl methacrylate onto silk using tetravalent cerium as initiator

The use of tetravalent ceric ions to initiate graft-copolymerization of methyl methacrylate onto silk has been investigated. The rate of grafting has been determined by varying monomer, cerium (IV), temperature, and nature of silk. The graft yield increases with increasing monomer concentration up to 0.65 mol/l and with further increase of monomer, the graft yield decreases. The percentage of grafting increases with increasing ceric ion concentration up to 0.03 mol/l and thereafter it decreases. The rate of reaction is temperature dependent, with increasing temperature, the graft yield increases. The grafting is considerably influenced by chemical modification prior to grafting. The effect of different species of ceric ion and CuSO₄ on the rate of grafting has also been investigated.     

Syntheses and properties of graft polymers of N‐substituted acrylamides onto EPDM

The graft polymerizations of N‐isopropylacrylamide (NIPAM) or N‐phenylacrylamide (NPAM) onto ethylene‐propylene‐diene terpolymer (EPDM) were carried out with benzoyl peroxide (BPO) as an initiator in toluene or THF. The structures of synthesized graft polymers, EPDM‐g‐N‐isopropylacrylamide (ENIPAM) and EPDM‐g‐N‐phenylacrylamide (ENPAM), were identified by infrared (IR) spectroscopy. The effects of monomer concentration, reaction time, and initiator concentration were investigated on the graft polymerization. The highest graft efficiency of NIPAM was obtained at 0.75 mol/L of NIPAM, 4 g of EPDM, 3 wt % of BPO, and 70°C for 48 h and that of NPAM did not much change up to 0.75 mol/L of NPAM, 4 g of EPDM, 3 wt % of BPO, and 70°C for 72 h. The thermal decomposition temperatures, wettabilities, and tensile strengths of ENIPAM and ENPAM all decreased with an increasing concentration of NIPAM and NPAM moiety in the corresponding polymers, respectively. The morphologies of ENIPAM and ENPAM after irradiation showed many gel particles as compared with those of ENIPAM and ENPAM before irradiation. The UV light and ⁶⁰Co γ‐ray resistances of ENIPAM and ENPAM were worse than those of EPDM due to carbonyl group in NIPAM and NPAM. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3259–3267, 1999     

Surface graft polymerization of ionic monomers onto poly(ethylene terephthalate) by UV-irradiation without degassing

Graft polymerization of anionic and cationic monomers was performed onto the surface of poly(ethylene terephthalate) (PET) film with a simultaneous UV irradiation method, but using no photo-sensitizer. To effect graft polymerization, the PET film was immersed in an aqueous solution containing a monomer and periodate (NaIO₄) of appropriate concentrations, followed by UV irradiation without degassing. The monomers used were 2-acrylamide-2-methylpropane sulfonic acid and acrylic acid as anionic and N,N-dimethyl aminopropyl acrylamide and dimethyl aminoethyl methacrylate as cationic monomer. The role of NaIO₄ at the polymerization was to make the concentration of oxygen dissolved in solution zero by the photochemical reaction with the oxygen. The surface structure of grafted films was characterized by their contact angle, dyeing, X-ray photoelectron spectroscopy, and zeta potentials. Graft polymerization took place, not merely on the outermost surface, but also within the thin surface region of the PET film without any change in bulk properties. © 1993 John Wiley & Sons, Inc.     

Grafting vinyl monomers onto silk fibers. X. Graft copolymerization of methyl methacrylate onto silk using hydrogen peroxide–thiourea redox system

The graft copolymerization of methyl methacrylate onto silk fibers initiated by a hydrogen peroxide–thiourea redox system was investigated under various conditions. The effects of monomer, initiator, temperature, acidity of the medium, and solvent on the rate of grafting were studied. The graft yield increases with the increase of monomer and initiator concentration. The graft yield also increases with the increase of acid concentration upto 22.50 × 10^?2M and thereafter it decreases. The effect of some inorganic salts on the rate of grafting has also been investigated, and a suitable mechanism has been suggested.     

Grafting of cyclodextrins onto polypropylene nonwoven fabrics for the manufacture of reactive filters. I. Synthesis parameters

A novel method for the preparation of immobilized α‐, β‐, and γ‐cyclodextrins (α‐, β‐, or γ‐CD) on polypropylene (PP) nonwoven fabrics is presented. These new materials were prepared by graft‐polymerization of glycidyl methacrylate (GMA) onto PP filters using the electron‐beam technique, followed by coupling of α‐, β‐, and γ‐CDs with the epoxide group. Optimization of various reaction parameters such as time, temperature, irradiation dose, monomer, and CD concentration was carried out. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2118–2125, 2000     

超声-微波共辐射法合成纤维素-MMA接枝共聚物

引言纤维素作为一种天然的可再生高分子材料,存在于丰富的绿色植物中,是自然界取之不尽用之不竭的清洁资源。因此,在煤、石油、天然气的储量日益减少的今天,纤维素可作为一种可持续发展的绿色资源来研究和开发。而且天然植物纤维资源丰富、价格低廉,并且具有较好的生物可降解性,在     

Graft copolymerization and characterization of 2‐hydroxyethyl methacrylate onto jute fiber by photoirradiation

UV radiation induced graft copolymerization of 2‐hydroxyethyl methacrylate onto natural lignocellulose (jute) fiber was carried out by two methods: simultaneous irradiation and grafting and preirradiation grafting. 1‐Hydroxycyclohexyl‐phenylketone was used as the photoinitiator in both methods. In the former method, the variation of the graft weight was measured for different values of radiation exposure time and the concentrations of both the monomer and photoinitiator. The latter method produced up to 76% graft weight compared to 45% obtained with the former method. The preirradiation method offers better control of the homopolymerization reaction compared to that afforded by the other method. The optimum value of the reaction parameters on the graft weight was evaluated. The mechanical properties of grafted samples were found to be drastically different from those of the as‐received ones and the effect was proportional to the percentage of graft weight. Differential scanning calorimetry studies showed that the percentage of graft add‐on of hydroxyethyl methacrylate with jute had a significant effect on the thermal properties. IR studies indicated the degree of grafting could be estimated by correlating the band intensities with the graft weight. The jute samples grafted with poly(hydroxyethyl methacrylate) at a level of 12% graft weight exhibited a maximum 20% increase in hydrophilicity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2898–2910, 2006     

Graft polymerization of polyvinylpyrrolidone onto silica

A new technique is reported for the surface grafting of polyvinylpyrrolidone (PVP) to hydroxylated solid surfaces. Free radical graft polymerization of vinylpyrrolidone onto vinylsilane–modified impermeable silica particles was carried out in an aqueous slurry reactor. The graft yield and the monomer conversion were determined by thermogravimetric analysis and UV spectroscopy, respectively. The graft yield was shown to increase by increasing the initial monomer concentration. A comparison of the graft polymerization reaction with the adsorption of polyvinylpyrrolidone onto untreated, vinylsilane-modified, and PVP-grafted silica was performed.     

Photoinduced graft copolymerization. IX. Graft copolymerization of methyl methacrylate onto nylon 6 in the presence of pyridine–bromine charge–transfer complex as photoinitiator

Photoinduced graft copolymerization of methyl methacrylate onto nylon 6 was investigated by using pyridine–bromine (Py–Br₂) charge–transfer complex as initiator. The graft yield increased with increasing monomer and initiator concentration at the initial stages, and therefore it decreased. The initiator exponent was computed to be 0.5. The reaction was carried out at three different temperatures, and the overall activation energy was computed. A suitable mechanism has been suggested.     

The study of curing behavior and thermal properties for soybean oil fatty acid-modified glycidyl methacrylate

The characteristics of glycidyl methacrylate (GMA)–modifiers, including the polymerization properties, curing properties, and thermal stability, were studied. The degree of crosslinkage for (GMA–modifier)polyols increases with increasing hexamethoxymethylmelamine (HMMM) content and reaches maximum when HMMM content is about 40 wt %. The gels obtained from thermal free-radical polymerization for GMA-modifier monomer decrease with increasing acid value. UV curing experiments indicate that the energy of ultraviolet might be insufficient to promote the curing reaction through transetherification with short-term irradiation. Kinetic parameters for the thermal decomposition of the polymer were measured with TG thermograms. © 1993 John Wiley & Sons, Inc.