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Abstract
The free radical copolymerization of phenyl methacrylate (PhMA) witho-methylphenyl-methacrylate(o-MPhMA) ando-ethylphenyl methacrylate (o-EPhMA) was carried out and the enthalpies of copolymerization, overall rate constants and copolymerization parameters were determined for different molar ratios of comonomers in the temperature range 353–373 K.
Abstract
Differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to examine the thermal behavior of the multimonomer poly[2-(10-undecenoyloxy)ethyl methacrylate] (PUDEM) within the temperature range from -80 to 400C. DSC measurements indicated that the polymer side chains were able to crystallize in paraffinic phase. PUDEM, added to methyl methacrylate (MM), can effectively copolymerize with essentially no homopolymer produced as shown by DSC (single T g). The value of T g depends on the PUDEM content, degree of cross-linking and the presence of free MM in the cross-linked product.
Abstract
In the present communication we report on the radiation induced grafting of methyl methacrylate (MMA) onto irradiated isotactic polypropylene film (IPP) by Peroxidation method to prepared grafted membrane (IPP-g-MMA). The radioactive isotope 60Co was used as the source of gamma radiation. A plausible mechanism of grafting has been proposed. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of different reaction parameters such as radiation dose, inhibitor concentration, monomer concentration, reaction time and reaction temperature respectively. Maximum percentage of grafting (85%) was obtained at [radiation dose] = 25 kGy, [inhibitor concentration] = 0.04 wt%, [MMA] = 6 wt%, [Reaction Temperature] = 60 °C in a [Reaction time] of 120 min. The evidence of grafted membrane was characterized by Fourier transform infrared spectroscopy, Atomic force microscopy method, Scanning electron microscopy which indicates that MMA has been grafted onto IPP. Hydrolysis of the grafted membranes in 1 N NaOH transformed ester groups of the grafted membranes to carboxylic acid and hydroxyl groups to form hydrolyzed grafted membranes. Hydrolyzed grafted membranes were investigated for their swelling behavior. Swelling properties of the hydrolyzed grafted membranes were performed in different solvents such as water, N,N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO). Maximum percentage swelling value of IPP-g-MMA was observed in pure DMSO, followed by DMF and water.
Abstract
The relationship between transition temperatures and copolymer composition was studied by DSC. Three types of copolymers were studied: styrene-acrylonitrile (SAN), vinyl chloride-vinyl acetate (VC-VA), and ethylene vinyl acetate (EVA). SAN's and VC-VA's are amorphous copolymers, whereas EVA's are semi-crystalline copolymers. The variation of the glass transitions and the crystalline melting are discussed in this study.
Abstract
Polyethylene glycol methacrylate (PEGMA) with different polyethylene oxide units were grafted onto polypropylene (PP) films by a preirradiation grafting method. The effect of co-solvent system on the degree of grafting and water contact angle were determined, respectively. The grafted sample films were verified by Fourier Transform Infrared (FTIR) spectroscopy in the attenuated total reflectance mode (ATR). The biocompatibility and blood compatibility of the grafted PP films were evaluated by the determination of protein adsorption, platelet adsorption and thrombus.
Summary This paper reports the investigation of the thermal stability of a series of new complexes with mixed ligands of the type M(phen)(C3H3O2)2(H2O)y ((1) M=Mn, y=0; (2) M=Ni, y=2; (3) M=Cu, y=1; (4) M=Zn, y=2; phen=phenanthroline and C3H3O2 is acrylate anion). The thermal behaviour steps were investigated. The thermal transformations are complex processes according to TG and DTG curves including dehydration, oxidative condensation of acrylate and thermolysis processes. The final products of decomposition are the most stable metal oxides.
Abstract
An intelligent hydrogel with both pH and temperature sensitivity was obtained by grafting acrylic acid and dimethylaminoethylmethacrylate onto preirradiated polypropylene (PP) film by two-step reactions. The effect of first and second reactions on the degree of grafting was studied. The grafted sample films were checked by Fourier transform infrared spectrophotometry in the attenuated total reflectance mode. The morphology of the PP samples was observed by scanning electron microscope in different conditions before and after grafting, respectively.
Abstract
Non-isothermal differential scanning calorimetry (DSC) experiments were performed to study the kinetics of the curing process of mixtures of diglycidylether of bisphenol A (DGEBA) and γ-butyrolactone (γ-BL) with ytterbium triflate as an initiator. It can be deduced that the cured material consists of epoxide homopolymers with incorporated poly(ether-ester) unities, which come from the lactone incorporated into the network. The kinetic parameters, obtained using the non-isothermal isoconversional procedure, show not only the importance of the proportion of initiator but also the influence of γ-butyrolactone on the polymerization of DGEBA. The homopolymerization of DGEBA catalyzed by ytterbium triflate has an activation energy of 85.3 kJ mol−1, which decreases to 68.2 kJ mol−1 in the presence of γ-butyrolactone forming copolymers. Analysis from DSC and FTIR data showed that, when the proportion of ytterbium triflate was increased, the reaction process accelerated and the mechanism of the cationic non-linear polymerization named activated monomer (AM) became more evident than the activated chain-end mechanism (ACE). Finally, the activation energies and the pre-exponential factors were determined for both mechanisms.
fumarate groups. This is desirable phenomenon, as fumarate forms are more reactive in copolymerization process with vinyl monomer. It has a favorable effect on thermal and mechanical properties of obtained materials [ 3 – 5 ]. In the unsaturated polyester
copolymerization in the form of polymeric microspheres for chromatography [ 16 – 20 ]. Owing to the fact that methacrylate derivatives are widely used as monomers for photo-polymerization, it was tried to use the new compounds for the synthesis of photo