Studies on graft copolymerization of 2-hydroxyethyl methacrylate onto poly(vinyl chloride)

Poly(vinyl chloride) was dehydrochlorinated in alkali solution and then grafted with 2-hydroxyethyl methacrylate (HEMA) using benzoyl peroxide as a free-radical initiator under a nitrogen atmosphere. The investigations involved examining the effects of grafting efficiency on various conditions, such as degree of dehydrochlorination, HEMA concentration, solvent effect, and reaction time. Maximum grafting to the extent of 57.2% was obtained. The mixed solvent grafting was attempted. © 1994 John Wiley & Sons, Inc.     

Photo-induced graft copolymerization of methyl methacrylate on poly(vinyl alcohol)

Photo-induced graft copolymerization of methyl methacrylate on poly(vinyl alcohol) (PVA) was examined in aqueous solutions. In unoxidized samples, only a few percent of PVA used took part in the formation of grafts, and the percent grafting was very low. However, if Fe²⁺, Fe³⁺, anthraquinone-2,7-disulfonate, or oxalic acid was used as sensitizer, the percent grafting was somewhat improved. Among them, the effect of Fe³⁺ was most remarkable. Oxidized PVA showed a higher initiating activity and was more susceptible to the sensitizing action of Fe³⁺ than unoxidized PVA. As Fe³⁺ has an ability to accelerate the photo-induced scission reaction of PVA chains for both oxidized and unoxidized PVA, it is thought to be very probable that the copolymer formed in the photo-induced systems has a block polymer-type structure like that in systems initiated by ceric ion or hydrogen peroxide.     

Studies on graft copolymerization of glycidyl methacrylate onto poly(vinyl chloride) and curing behavior of its grafted copolymer

Poly(vinyl chloride) was dehydrochlorinated in an alkali solution and then grafted with glycidyl methacrylate (GMA) using benzol peroxide as the free-radical initator under a nitrogen atmosphere. The efficiency of grafting GMA under the influence of an alkali, GMA concentration, and duration of the grafting reaction, the viscosity properties, and the curing behavior with diamine were investigated. Maximum grafting to the extent of 46.4% was obtained. The optimum curing reaction condition were investigated. © 1995 John Wiley & Sons, Inc.     

Photo-induced graft copolymerization of methyl methacrylate on oxidized poly(vinyl alcohol) fiber

Photo-induced graft copolymerization of methyl methacrylate on oxidized poly(vinyl alcohol) fiber was investigated. Oxidation of the fiber sample with sodium hypochlorite or periodic acid led the radical formation by photo-irradiation to intensify markedly. ESR spectra of the irradiated oxidized sample proved that a considerable amount of triplet component radical was contained in it, whereas the unoxidized sample mostly indicated a singlet. The spectra found in the irradiated unoxidized sample was assigned to two radicals, I and II, and for the oxidized sample, to III and IV. The spectrum for I must be a singlet, and a triplet for II, III, and IV. Among the last three, II was less stable toward heat. As the oxidized sample has a high activity for photoinitiation, the radicals of III and IV are presumed to be the sites of graft copolymerization:      

Gamma radiation induced graft copolymerization of acrylamide onto poly(vinyl chloride) films

Grafting of acrylamide (AAm) onto poly(vinyl chloride) (PVC) films using gamma radiation has been carried out. The effects of different parameters on the graft yield have been investigated. These parameters include radiation dose, monomer concentration, solvent composition, types of inhibitors and acidity of the medium. In addition, the effects of the multifunctional monomers N,N′-methylene allyl amide (MAAm) and 2,4,6-triallyloxy-1,3,5 triazine (TARA) on the graft yield have been investigated. It has been found that methanol/water mixture in the ratio (1:1) is the proper diluent mixture for enhancing the graft copolymerization process. The presence of sulphuric acid in the reaction medium adversely affects the graft yield more than acetic acid. The presence of MAAm in the reaction medium markedly increases the graft yield, while TARA has practically no effect on the grafting process. Grafted films have been characterized and evidence of grafting has been obtained using thermal and spectroscopic analysis together with swelling measurements in water. © 1998 SCI.     

Mechanochemical block copolymerization of poly(vinyl chloride) with methyl methacrylate by ultrasonic irradiation

Summary Mechanical degradation and mechanochemical block copolymerization in systems of poly(vinyl chloride)-methyl methacrylate-solvents have been studied by ultrasonic irradiation at 60°C. The effect of the concentrations of poly(vinyl chloride) on mechanical degradation was investigated. In addition, the effects of poly(vinyl chloride) and methyl methacrylate concentrations on mechanochemical block copolymerization were investigated. The rate equation for mechanochemical block copolymerization has been deduced, and the experimental results were in fairly good agreement with the equation. The changes in the composition of the block copolymer and homopolymers in the reaction products were followed by turbidimetric titration.     

Surface graft copolymerization of poly(methyl methacrylate) onto waste tire rubber powder through ozonization

Grinding of tires offers a promising opportunity for recycling waste rubber because fine waste tire rubber particle may be used as fillers and property modifiers in thermoplastic, elastomer, and thermoset blends. However, due to the lack of reactive sites on the WTR surface, the adhesion between WTR powder and matrix is poor. In this article, ozonization of waste tire rubber (WTR) powder was performed to produce some “immobile” reactive points (hydroperoxide groups) on the WTR surface. The free radical generated by the decomposition of hydroperoxide groups on WTR surface, was used to initiate graft polymerization of methyl methacrylate (MMA) onto the surface of WTR powder. The experimental results showed that MMA was successfully grafted onto the surface of WTR. The hydrophilicity of the MMA grafted WTR (MMA‐g‐WTR) was improved. The concentration of hydroperoxide groups and the graft degree were both increased with ozonization time. With increasing of polymerization time and polymerization temperature, the grafting degree increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Hexavalent-chromium-initiated graft copolymerization of methyl methacrylate onto cellulose

Graft copolymerization of methyl methacrylate (MMA) onto cotton–cellulose has been carried out using hexavalent chromium Cr(VI) as initiator. Aqueous-methanolic solution of perchloric acid has been chosen as the reaction medium. The effect of monomer, initiator, acid, reaction medium, and temperature on the graft percentage has been found out. The reactions have also been carried out in the presence of polymerization, inhibitors, and retarders, such as hydroquinone and transition metal salts like CuSO₄, FeCl₃, etc. The grafted samples, after exhaustive separation of homopolymers and purification, were subjected to various chemical, mechanical, and thermal testings. The results of various analyses have been compared with the reference, and the improvement in the graft has been evaluated. A suitable mechanism for the grafting processes has been suggested, in accordance with the experimental results.     

Surface modification of poly(vinyl chloride) with poly(methyl methacrylate)/poly(dimethyl siloxane) graft copolymers

X-ray photoelectron spectroscopy is used to study the surface segregation of siloxane in dilute blends of poly(methyl methacrylate)/poly(dimethyl siloxane) graft copolymers in poly(vinyl chloride)(PVC). The graft copolymers are found to be extremely efficient surface modifiers, which form, when added in amounts of 0.5% or more, a continuous siloxane overlayer on the surface of PVC. © 1995 John Wiley & Sons, Inc.     

Free volume microprobe studies on poly(methyl methacrylate)/poly(vinyl chloride) and poly(vinyl chloride)/polystyrene blends

Blends of Poly(methyl methacrylate) (PMMA)/Poly(vinyl chloride) (PVC) and Poly(vinyl chloride) (PVC)/Polystyrene (PS) of different compositions were prepared by solution casting technique. The blends were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and Positron Lifetime Spectroscopy. DSC data were found to be inadequate to describe whether PMMA/PVC blends are miscible or not, possibly because of the small gap in their glass transition temperatures. On the other hand, PVC/PS blends were clearly found to be immiscible by DSC. FTIR results for PMMA/PVC indicate the possible interactions between the carbonyl group of PMMA and α‐hydrogen of PVC. Free volume data derived from Positron lifetime measurements showed that the PMMA/PVC blends to be miscible in low PVC concentration domain. For the first time, the authors have evaluated the hydrodynamic interaction parameter α, advocated by Wolf and Schnell, Polymer, 42, 8599 (2001), to take into account the friction between the component molecules using the free volume data. This parameter (α) has a high value (?57) at 10 wt% of PVC, which could be taken to read miscibility for PMMA/PVC blends to be high. In the case of PVC/PS blends, the positron results fully support the DSC data to conclude the blends to be immiscible throughout the range of concentration. As expected, the hydrodynamic interaction parameter α does not show any change throughout the concentration in PVC/PS blends, further supporting the idea that α is another suitable parameter in the miscibility study of polymer blends. POLYM. ENG. SCI., 46:1231–1241, 2006. © 2006 Society of Plastics Engineers     

Graft copolymerization of N‐isopropylacrylamide onto poly(vinyl chloride)

Poly(vinyl chloride) (PVC) was dehydrochlorinated in alkali solution and then grafted with N‐isopropylacrylamide (NIPAM) using benzoyl peroxide as an initiator under a nitrogen atmosphere. The results show that grafting of NIPAM onto dehydrochlorinated PVC (DHPVC) by means of chemical initiation is easily performed. The influence of various reaction conditions such as NIPAM concentration, reaction time, initiator concentration, and PVC content on the grafting copolymerization was investigated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1234–1241, 1999     

A study on graft copolymerization of methyl methacrylate onto jute fiber

A kinetic study of the graft copolymerization of methyl methacrylate onto jute fiber using KMnO₄–malonic acid redox initiator system has been made. Effects of the concentrations of malonic acid, monomer, and KMnO₄ on graft yield have been studied. Besides, the effects of temperature, acid, and reaction medium, some inorganic salts on graft yield have been investigated. The most remarkable features of the investigation include the proposition of a mechanism, derivation of rate expression for the grafting process, and characterization of the grafted fiber by thermogravimetric analysis.     

Studies on miscibility of poly(vinyl chloride) with natural rubber-graft-polyacrylonitrile and natural rubber-graft-poly(methyl methacrylate)

The miscibility of poly(vinyl chloride)/natural rubber-graft-polyacrylonitrile (PVC/NRPACN) and PVC/NR-graft-poly(methyl methacrylate) (PMMA) were studied by differential scanning calorimetry (DSC) and viscometry. DSC curves of PVC/NR graft copolymer blends showed a major endotherm at about 265°C that was assigned to the thermal decomposition of PVC. PVC/NRPMMA blends showed a minor endothermic peak at about 124°C and the PVC/NRPACN blends showed a broad peak (which develops into two peaks) at about 160°–180°C, respectively. Absolute viscosity versus weight percent PVC plots of the two sets of blends were nonlinear. X-ray diffraction patterns of the PVC/NRPACN blends showed overlapping spacings due to the constituent polymers. Phase-contrast micrographs of the PVC/NRPACN blends showed gross phase discontinuity. The heats of mixing solutions of PVC blended with NRPMMA were found to be well above the upper limit of miscibility. © 1996 John Wiley & Sons, Inc.     

Studies on graft copolymerization of cyclohexyl methacrylate onto chloroprene rubber

Graft copolymerization of cyclohexyl methacrylate (CMA) onto chloroprene rubber (CR) was carried out in toluene using benzoyl peroxide as an initiator. The graft copolymer was isolated from the gross polymer by extracting it with a butanone solution. Infrared (IR) spectra of the graft copolymer showed the occurrence of grafting. Optimization of various parameters of the grafting, namely, time, temperature, and initiator concentrations, was performed. The mechanical adhesive properties of the graft copolymer, CR-g-CMA, were measured and compared with those of the graft copolymer of methyl methacrylate (MMA) onto CR, CR-g-MMA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1733–1737, 1997     

Studies on graft copolymerization of cyclohexyl methacrylate onto 1,2-polybutadiene

The free radical grafting of cyclohexyl methacrylate (CMA) onto 1,2-polybutadiene (1,2-PBD) in benzene solution at 60°C was studied. The graft copolymer was characterized by IR, NMR, DSC, and intrinsic viscosity measurements. The polymerization of CMA shows normal kinetic behavior when the PBD concentration is kept below 1.0 monomer mol/L. The rate of grafting was determined at different reaction times, monomer concentrations, initiator concentrations, backbone concentrations, temperatures, and concentrations of the zinc chloride additive. The performance of the graft copolymer used as adhesive was also investigated for bonding of PVC/PVC film.     

Influence of tacticity of poly(methyl methacrylate) on the compatibility with poly(vinyl chloride)

Blends of conventional poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) with different tacticities were obtained both from the bulk and from solution. The glass transition temperatures (T_g) of the blends were determined with a differential scanning calorimeter and by dynamic mechanical measurements. Some turbidity measurements on films and viscosity measurements on mixed solutions supplied additional information about the state of mixing. From the results it appeared that isotactic (i-)PMMA and PVC form an incompatible system over the entire composition range (two T_g's), whereas blends of syndiotactic (s-)PMMA and PVC form a compatible system up to a composition corresponding with a monomer unit ratio of about 1:1. For higher s-PMMA contents phase separation is observed; one phase corresponding with the 1:1 s-PMMA—PVC associate and the other phase representing the excess of pure s-PMMA. This effect of tacticity is discussed in terms of the differences in chain conformation of i- and s-PMMA.     

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。     

Dynamic mechanical behavior of poly(vinyl chloride)/poly(methyl methacrylate) polymer blend

A poly(vinyl chloride) (PVC)/poly(methyl methacrylate) (PMMA) (80/20 w/w) polymer blend was studied by mechanical spectroscopy. Two relaxations can be distinguished: in the glassy state, a very large secondary relaxation in the range of 100 K to 325 K which results from the combination of secondary relaxations of PVC and PMMA; and only one main relaxation at 364 K associated to the glass rubber transition. The relaxation spectrum in the range of the β relaxation has been described by a relaxation time distribution function based upon a Gaussian function and a series-parallel model. The α relaxation was studied by means of a theoretical approach for the nonelastic deformation of polymers. We found that the miscibility of this blend appears to be a function of the observation scale: the PVC/PMMA blend is heterogeneous at the scale of molecular movements involved for the β relaxation process but homogeneous at the scale of the chain segments responsible for the α relaxation dynamics. © 1996 John Wiley & Sons, Inc.     

Trivalent manganese chelate-initiated graft copolymerization of methyl methacrylate onto silk fibers

The graft copolymerization of methyl methacrylate onto silk fibers was investigated in aqueous solution using Mn³⁺ acetyl acetonate [Mn(acac)₃] as initiator. The rate of grafting was determined by varying monomer, acidity of medium, temperature, and reaction medium. The graft yield increases significantly with increase of [Mn(acac)₃] concentration up to 0.01M, and with further increase of [Mn(acac)₃] the graft yield decreases. The effect of the increase of monomer concentration brings about a significant enhancement in the graft yield, and with further increase the graft yield decreases. The rate of reaction is temperature dependent; with increasing temperature, the graft yield increases. Among the solvent composition studied, a water/solvent mixture containing 10% of the solvent seems to constitute the most favorable medium for grafting, and, with further increase of solvent composition, the graft yield decreases. The effect of some inorganic salts, organic solvents, and complexing agents has been investigated.     

Influence of the tacticity of poly(methyl methacrylate) on the miscibility with poly(vinyl chloride)

It can be concluded from the work of Schurer et al.¹⁰ that poly(vinyl chloride) (PVC) is more miscible with syndiotactic than with isotactic poly(methyl methacrylate) (PMMA). By choosing different molar masses for the various tactic forms of PMMA it is possible to obtain blends with PVC with similar phase behaviour, i.e. in all cases a cloud-point curve with a minimum in the vicinity of 190°C. In this way a more quantitative statement about the influence of the tacticity of PMMA on its miscibility with PVC can be made. One of the principal differences between syndiotactic or atactic PMMA and isotactic PMMA is the higher flexibility of the latter. Using Flory's equation of state theory it will be shown that the effect of this difference is large enough to explain the difference in phase behaviour observed. Heats of mixing of low molar mass analogues were also measured and found to be negative.