Allil kopolimerleriin sentezi karakterizasyonu ve ahşap yapının korunmasındaki kullanılabilirliği

Abstract

Ill SUMMARY Despite its various useful properties, wood also possesses some disadvantages. In order to consolidate and conserve wooden objects, monomers and monomer mixtures compatible with the structure of wood have been impregnated and in situ polymerized. In this study, new monomeric systems have been tried. Homopolymerization of allyl 2,3 epoxy propyl ether (AE) which was initiated by gama rays and copolymerization of allyl 2,3 epoxy propyl ether (AE) and allyl alcohol (AA) with methyl methacrylate (MMA) and acrylonitrile (AN) were investigated. Homo and copolymers thus obtained were characterized by Fourier Transform Infrared (FTIR), Ultraviolet (UV) spectroscopies and Thermal Analysis techniques. Molecular weights of these copolymers couldn't be measured due to their insolubilities. The reactivity ratios of monomer pairs (AA+AN and AE+AN) which copolymerized heterogeneously were calculated by determining compositions by Elementel analysis and applying Non-linear least square method. The values of rj and t% of monomers used in the copolymerization of AN+AA were 2.09 and 0.40 and AN+AEwere 2.33 and 0.34 respectively. Thermal stabilities of homopolymers and copolymers were determined and single glass transition temperatures were observed for copolymers. Thermal stabilities of copolymers obtained from AA+AN and AE+AN monomers were higher than those of copolymers formed from AA+MMA and AE+MMA monomer mixtures. AA+AN, AA+MMA, AE+AN and AE+MMA monomer mixtures were used to conserve and consolidate the wood. Following the impregnation of these monomer mixtures to four types of wood which were hard (beech, oak) and soft (spruce, cedar) in their strength, polymerization was accomplished by gamma irradiation. The fine structure of wood+polymer(copolymer) composites were investigated by Scanning Electron Microscopy. It has been observed that copolymers obtained from AA+MMA and AE+MMA mixtures showed the optimum compatibility. In the presence of polymers and copolymers wood did not gain significant thermal stability. The compression strength and Brineli Hardness Numbers determined for untreated and treated wood samples indicated that the mechanical strength ofIV wood+polymer(copolymer) composites vere increased. It was found that the mechanical strength of the wood samples containinig AE+AN and AE+MMA copolymers was higher than the others. After 28 days of ageing procedure there were no significant changes in the mechanical stability and Brineil Hardness Numbers of composites. The capacity of water uptake of wood+polymer( copolymer) composites were observed to decrease by more than 50% as compared to original samples. High amount of copolymers loading of spruce and cedar provided a decrease of 30% in the water uptake from an initial value of 100%. As a consequence, it was observed that all monomer couples used in this study increased the mechanical strength of the wood decreased water uptake capacity and protected the samples against ageing and biodegradation. It was also found that AE+MMA copolymers were the best to protect the wood against various environmental attacks.

Ill SUMMARY Despite its various useful properties, wood also possesses some disadvantages. In order to consolidate and conserve wooden objects, monomers and monomer mixtures compatible with the structure of wood have been impregnated and in situ polymerized. In this study, new monomeric systems have been tried. Homopolymerization of allyl 2,3 epoxy propyl ether (AE) which was initiated by gama rays and copolymerization of allyl 2,3 epoxy propyl ether (AE) and allyl alcohol (AA) with methyl methacrylate (MMA) and acrylonitrile (AN) were investigated. Homo and copolymers thus obtained were characterized by Fourier Transform Infrared (FTIR), Ultraviolet (UV) spectroscopies and Thermal Analysis techniques. Molecular weights of these copolymers couldn't be measured due to their insolubilities. The reactivity ratios of monomer pairs (AA+AN and AE+AN) which copolymerized heterogeneously were calculated by determining compositions by Elementel analysis and applying Non-linear least square method. The values of rj and t% of monomers used in the copolymerization of AN+AA were 2.09 and 0.40 and AN+AEwere 2.33 and 0.34 respectively. Thermal stabilities of homopolymers and copolymers were determined and single glass transition temperatures were observed for copolymers. Thermal stabilities of copolymers obtained from AA+AN and AE+AN monomers were higher than those of copolymers formed from AA+MMA and AE+MMA monomer mixtures. AA+AN, AA+MMA, AE+AN and AE+MMA monomer mixtures were used to conserve and consolidate the wood. Following the impregnation of these monomer mixtures to four types of wood which were hard (beech, oak) and soft (spruce, cedar) in their strength, polymerization was accomplished by gamma irradiation. The fine structure of wood+polymer(copolymer) composites were investigated by Scanning Electron Microscopy. It has been observed that copolymers obtained from AA+MMA and AE+MMA mixtures showed the optimum compatibility. In the presence of polymers and copolymers wood did not gain significant thermal stability. The compression strength and Brineli Hardness Numbers determined for untreated and treated wood samples indicated that the mechanical strength ofIV wood+polymer(copolymer) composites vere increased. It was found that the mechanical strength of the wood samples containinig AE+AN and AE+MMA copolymers was higher than the others. After 28 days of ageing procedure there were no significant changes in the mechanical stability and Brineil Hardness Numbers of composites. The capacity of water uptake of wood+polymer( copolymer) composites were observed to decrease by more than 50% as compared to original samples. High amount of copolymers loading of spruce and cedar provided a decrease of 30% in the water uptake from an initial value of 100%. As a consequence, it was observed that all monomer couples used in this study increased the mechanical strength of the wood decreased water uptake capacity and protected the samples against ageing and biodegradation. It was also found that AE+MMA copolymers were the best to protect the wood against various environmental attacks.