Properties Of Graft Copolymers Research Articles

Sorptive properties of cellulose fibres modified by grafting on poly-2-methyl-5-vinyltetrazole

The sorption properties of graft copolymers of cellulose and poly-2-methyl-5-vinyltetrazole (poly-2-MVT) prepared by grafting onto hydrocellulose fibre or natural cellulose have been investigated.

Stress–strain properties of graft copolymers of polyethylene and acrylic acid

Stress–strain properties of graft copolymers of polyethylene and acrylic acid

Some Properties of Graft Copolymers

Abstract Some properties of poly(vinyl chloride)- g-polyisobutylene graft copolymers are reviewed. The heat stability of polyvinyl chloride)-g-polyisobutylene (PVC-g-PIB) is shown in Fig. 1. There is improvement in heat stability after grafting. We think that the removal of the variety of defect sites reduces the thermal sensitivity of this material. Another interesting observation was one which is difficult to express quantitatively. This was that the equipment after the experiment was extremely clean, with little, if any, cleaning necessary after completion of the extrusion experiment.

Anionic Graft Copolymerization of 2-Vinylpyridine by Metallated Polymer and Some Properties of Graft Copolymers

2-Vinylpyridine was grafted anionically by and onto lithiated poly(styrene-co-p-benzylstyrene)having known molecular weight (M.) and the narrow-molecu1ar weight distribution. The yield in each run was about 100%o. The results of the M. measurement and the turbidimetric titration showed that the graft copolymer was the only product. On the assumption that the number of the branches of the graft copolymer is nearly equal to (anion number/molecule) of metallated polymer, M. of the branches of graft copolymer was calculated. Graft copolymers having knewn chemical composition, known molecular structure and multi-branches could be synthesized by the above-mentioned method.The solubility and intrinsic viscositses ([T]) of graft copolymers depended on their molecular structure. [op] values of graft copolymers in benzene at 300C were smaller than those expected on the basis of their M. values. The intrinsic viscosities were affected mainly by M. of branches and M. of backbone, but hardly by the number of branches. The solubility of graft copolymers was higher than that of poly(2-vinylpyridine) and lower than that of poly(styrenecop-benzylstyrene) in a mixed solvent of 2-butanone and n-heptane. lt shows that backbone Segments protect the branch segments from precipitation. On graft copolymers having the same M. and the same chemical composition, the solubility of the graft copolymer having the higher M. of branches was lower than that of the graft copolymer having the smaller of branches.

Comparison of monomolecular film properties of graft copolymers of polyvinyl pyrrolidone-polyvinyl acetate and physical mixtures of the component homopolymers

Comparison of monomolecular film properties of graft copolymers of polyvinyl pyrrolidone-polyvinyl acetate and physical mixtures of the component homopolymers

Mechanical Properties of Reduced Wool and Methyl Methacrylate Graft Copolymers

Graft copolymeriration of methyl methacrylate was performed onto wool reduced by various chemicals using ferrous ammonium sulfate and hydrogen peroxide redox system at 45°C temperature. Reduced wools show higher percentage of polymer deposition as compared to natural because the thiol groups act as graft centers. Mechanical properties of MMA-reduced wool graft copolymers were studied. Results indicate that, with approximately 50% graft copolymeriza tion, the decrease in elongation is considerably high and the tensile strength is decreased slightly. In case of modulus, an initial increase with polymer deposition followed by a decrease. Density and moisture regain were also determined and the results were discussed in relation to mechanical properties of graft copolymers.

Mechanical Properties of Graft Copolymers of Methyl Methacrylate and Modified Wool

Graft copolymerization of methyl methacrylate was performed onto wool chemically modified with caustic soda, formic acid, thioglycollic acid, and sodium bisulfite using ferrous ion-hydrogen peroxide redox system at 45°C. The percent graft-on was found to be higher in modified fibers. The graft-on increases with reaction time up to about 10 hr. Some mechanical properties of such graft copolymers were studied. With polymer formation, the strength decreases a little, probably due to the initiator free radicals; the breaking elongation falls considerably, particularly in reduced fibers. The Young's static modulus decreases after acid and alkali treatment and increases after reduction. The modulus is found to decrease slightly with graft-on in normal, alkali-treated and formic acid-treated wool. However, in case of reduced wool, an initial increase of modulus with polymer uptake is followed by a decrease.

Synthesis and study of the physicochemical properties of graft copolymers of cellulose with polyvinylacetate

Synthesis and study of the physicochemical properties of graft copolymers of cellulose with polyvinylacetate

The fibre-forming properties of graft co-polymers of polyacrylonitrile and their mixtures with homopolymers

The fibre-forming properties of graft co-polymers of polyacrylonitrile and their mixtures with homopolymers

Some Recent Advances in Pure and Applied Aspects of Graft Copolymers

Abstract In recent years more attention has been given to the preparation and characterization of graft copolymers and an examination of their properties than to developing novel methods of synthesis. In particular, these property studies can be used to develop applications of graft copolymers. The methods used to prepare and characterize better defined grafts are briefly reviewed. The structure of most graft copolymers is such that considerable amounts of one polymer can be grafted to another without affecting greatly the main properties of that polymer. In this way, the properties of one polymer such as higher water absorption can be imparted to another without changing the mechanical properties, for example, of the second polymer. Some other inherent properties of graft copolymers are discussed, including their compatibility with the parent homopolymers, their possible con-formational changes, and other features. Finally, the use of the special nature of graft copolymers for the modification of the bar...

Effect of the length of grafted chains and of the amount of homopolymer on the properties of graft copolymers

Effect of the length of grafted chains and of the amount of homopolymer on the properties of graft copolymers

Synthesis and study of the physicochemical properties of graft copolymers of acetyl cellulose and 2-vinyl pyridine

Synthesis and study of the physicochemical properties of graft copolymers of acetyl cellulose and 2-vinyl pyridine

The synthesis, characteristics and some properties of graft copolymers of cellulose acetate and poly-2-methyl-5-vinylpyridine

The synthesis, characteristics and some properties of graft copolymers of cellulose acetate and poly-2-methyl-5-vinylpyridine

酢酸セルロースーアクリル酸エステル系グラフトポリマーの二三の性質

酢酸セルロースーアクリル酸エステル系グラフトポリマーの二三の性質

Solid‐State Properties of Graft Copolymers

Solid‐State Properties of Graft Copolymers

The synthesis and properties of isotactic-atactic polystyrene graft copolymers

RECENT studies of the properties of graft copolymers has enabled certain general characteristics of this class of polymers to be explained.We have shown previously [1-5] on the example of graft eopolymers of the amphipathic type that their structural and thermomechanical properties are a distinctive combination of the properties of the two components. At the same time the solubility of these eopolymers is considerably reduced and this is explained by the mutual screening effect of the components [3, 6]. In our work in this field the graft eopolymers studied were obtained from components differing widely both in chemical nature and physical properties (for example polystyrene-polyacrylic acid and polystyrenepolyvinylalcohol grafts, etc. [1-6] and moreover in these systems one of the polymeric components was a polymer with a rigid chain and a glass temperature (Tg) above its decomposition temperature. Furthermore both homopolymers were non-crystalline systems of irregular structure [3-6]. I t was of interest to s tudy the properties of a graft copolymer consisting of chains of the same chemical nature but possessing different structures. Copolymers of crystalline, isotactie (main chain) and amorphous, atactic (side chains) polystyrene were chosen for the present work. I t is known that in ordinary, atactic polystyrene the high-elastic state is covered by a temperature interval of 50 ° (Tg90°; T m 140°). For crystallized, isotactic polystyrene, with the same chemical structure but a different spatial arrangement of the asymmetric carbon atoms in the backbone (dd or ll) the total absence of the high-elastic state is characteristic, but on the other hand the melting point (230 ° ) is high. On conversion to the amorphous state, when heated above its T~ (90°), this polymer again acquires the properties of a rigid plastic [7]. On grafting on to crystalline, isotactic polystyrene ataetic polystyrene chains, with their characteristic random sequence of asymmetric carbon atoms, the production of a graft copolymer with a well defined high-elastic region while maintaining a high melting point would be expected [5]. Such a graft copolymer would also provide a suitable model for the s tudy of the structural properties

Ordering processes in a system containing an isotactic-atactic polystyrene graft copolymer

THE elucidation in recent times of the basic interelationships of certain properties of graft copolymers [1] sets before investigators the task of making a detailed s tudy of the structure of such systems. One of the interesting problems in this field is the s tudy of the effect of chemical grafting on the ability of a polymer to crystallize when the corresponding homopolymer is a stereoregular, crystalline system. The scanty data in the literature on X-ray diffraction studies of graft copolymers, consisting of ordered and disordered components [2-7], indicate that if the main chain of the eopolymer is capable of crystallization and the side chains are composed of irregular macromolecules or vice versa, according to the X-ray diffraction data such copolymers can preserve their structural order even when there is a considerable content of the amorphous components. This is true, for example, of graft copo]ymers of amylose and methyl methacrylate [2], of hydroxyethylated nylon [5] and in certain other cases [1]. Let us examine the possible explanations of this phenomenon. First, in the case where grafting takes place under heterogeneous conditions on the surface of a crystalline polymer present in the system in the form of fine particles, fibres or films, which do not pass into solution when the graft copolymer is formed, it may be concluded from X-ray diffraction data that surface grafting of this type preserves the structural pat tern characteristic of the crystalline polymer itselL This type of grafting, taking place on the surface of crystalline aggregates of the first component should easily be achieved by the radiation and mechanochemical methods of preparation of graft copolymers, in which a polymer swollen with another monomer is used, and also by the method involving ozonization

Dynamic mechanical properties of graft copolymers of nylon

Dynamic mechanical properties of graft copolymers of nylon