The Effect of a Method of Dissolution of Graft Copolymer of Polyacrylonitrile and Poly(Methyl Acrylate) on Drawability and Properties of Spun Fibers

1976 ◽  
Vol 46 (10) ◽  
pp. 767-770
Author(s):  
Samy Abdel Monem El-Garf

It was found that dissolution of the graft copolymer has an effect on drawability and other properties of fibers spun from this graft copolymer. The resistance to double bending and abrasion resistance are considerably decreased with the increase of the dissolution temperature. The breaking properties were not greatly changed. The maximum loop and knotted yarn strength was reached when the polymer was dissolved by heating. These values are 100% and 99% of the original, respectively—higher than those obtained from PAN and PANM. The presence of 5% PMA in the side chains of the graft copolymer increased the flexibility of these chains. This is evident from the decrease of the initial modulus of elasticity from the values obtained for PANM and PAN.

1976 ◽  
Vol 46 (2) ◽  
pp. 77-81 ◽  
Author(s):  
Samy Abdel Monem El-Garf

Fibers were spun from graft copolymers of polyacrylonitrile and poly(methyl acrylate). Increasing poly(methyl acrylate) side chains from 5 to 8% decreased the viscosity of the spinning solution in dimethylformamide. The spinning solutions were unstable. When the graft copolymer contained 5% side chains, the viscosity of these solutions returned to almost its initial value by heating. Fibers were obtained from graft copolymers containing from 5–13% poly(methyl acrylate) side chains. These were formed at the temperature of the coagulation bath (50°C), while at temperatures less than 50°C the fibers were not obtained. Weak fibers were produced from a graft copolymer containing 13% side chains at the temperatures of the coagulation bath (20 and 50°C). No fibers were obtained from graft copolymer containing 25% side chains. The method of dissolution of the graft copolymers does affect the drawing of fibers produced from them. It was observed that the heating of the spinning solution decreases the amount of drawing of the produced fibers. The presence of the flexible side chains of poly(methyl acrylate) in the graft copolymer improves the maximum possible degree of drawing of the fibers relative to that of fibers from the initial linear copolymer and homopolyacrylonitrile.


e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Fatima Zohra Sebba ◽  
Seghier Ould Kada ◽  
Mohamed Benaicha ◽  
Nerjesse Nemiche

AbstractIn this study, 2-oxopropylmethacrylate-terminated poly(N-vinyl-2- pyrrolidone) is produced by cationic polymerization using HClO4 as an initiator. Termination (end capping) step is accomplished using 2- hydroxypropylmethacrylate (2HPMA) and the polymer product has different chain lengths of molecular weight averages ranging from 672 to 3049 g/mol. The study also synthesised amphipathic graft copolymers having hydrophobic poly(α- methylstyrene) as a backbone chain and hydrophilic poly(N-vinyl-2-pyrrolidone) (PVP) as side chains of various lengths. The copolymer synthesis was accomplished by free radical copolymerization of ω-oxopropylmethacrylate PVP in the presence of α-methyl styrene initiated with benzoyl peroxide. Measurements of the dynamic viscosity of the polymer solution (20% weight of macromonomers in ethanol) show that the viscosity is proportional to the average molecular weights M̅n . However, a reverse behaviour of the viscosity variation with regard to M̅n is observed for graft copolymer samples. The viscosity variation with respect to the graft copolymer mass must be due to steric effects, which are strongly pronounced in grafted copolymer chains. Appearance of the number of side chains attached to poly(α-methylstyrene) backbone reveals that the grafting reaction has occurred with good efficiency.


2015 ◽  
Vol 732 ◽  
pp. 161-164 ◽  
Author(s):  
Jan Vesely ◽  
Lukas Horny ◽  
Hynek Chlup ◽  
Milos Beran ◽  
Milan Krajicek ◽  
...  

The effects of the polyvinyl alcohol (PVA) concentration on mechanical properties of hydrogels based on blends of native or denatured collagen / PVA were examined. Blends of PVA with collagen were obtained by mixing the solutions in different ratios, using glycerol as a plasticizer. The solutions were cast on polystyrene plates and the solvent was allowed to evaporate at room temperature. Uniaxial tensile tests were performed in order to obtain the initial modulus of elasticity (up to deformation 0.1), the ultimate tensile stress and the deformation at failure of the material in the water-saturated hydrogel form. It was found that the material was elastic and the addition of PVA helped to enhance both the ultimate tensile stress and modulus of elasticity of the films. Samples prepared from denaturated collagen showed the higher ultimate tensile stress and the deformation at failure in comparison with those prepared from native collagen. The results suggest that we could expect successful application of the collagen/PVA biomaterial for tissue engineering.


2009 ◽  
Vol 44 (21) ◽  
pp. 5877-5884 ◽  
Author(s):  
Xi-yin Gao ◽  
Na Han ◽  
Xing-xiang Zhang ◽  
Wan-yong Yu

RSC Advances ◽  
2015 ◽  
Vol 5 (50) ◽  
pp. 39668-39676 ◽  
Author(s):  
Guolin Lu ◽  
Hao Liu ◽  
Haifeng Gao ◽  
Chun Feng ◽  
Yongjun Li ◽  
...  

Amphiphilic graft copolymers bearing a hydrophobic PMBTFVB backbone and hydrophilic PEG side chains were synthesized by Williamson reaction through the grafting-onto strategy.


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