PVC Chloride In Situ Grafting And Blending To Prepare Wood/PVC Adhesives,Structure And Properties

This paper uses two methods to prepare wood/PVC adhesives.One is to use chlorinated in-situ grafting method—polyvinyl chloride grafted with maleic anhydride（CPVC-cg-MAH）as the main body of the adhesive;the other is to use Chlorinated polyvinyl chloride（CPVC）and polymethyl methacrylate（PMMA）are blended and prepared.The preparation of CPVC-cg-MAH is different from the previous high temperature initiation,but it is initiated by low temperature ultraviolet light.The thesis explores the contribution of UV-induced and thermal-induced under low temperature conditions.Through ¹H-NMR analysis,it was found that the low temperature ultraviolet light can promote the grafting of MAH,and even make the grafting rate higher than the chlorine substitution rate;the chlorine substitution rate of the macromolecular chain increases with the increase of temperature;It has certain influence on the structure of CPVC-cg-MAH.The experimental results show that when the amount of SiO₂ is 12parts,it is most conducive to the grafting of CPVC-cg-MAH;the solvent provides good fluidity for the adhesive,helps the adhesive penetrate into the adhered material,and improves the bonding performance.For the polymer with the special structure of CPVC-cg-MAH,it is difficult for a single solvent to meet the requirement of complete dissolution.Aiming at this problem,this topic proposes a tetrahydrofuran/1,2-dichloroethane composite solvent based on the principle of similar solubility parameters,which can completely dissolve CPVC-cg-MAH and provide excellent dissolution performance.As an adhesive,the adhesive strength is very important.In this paper,the adhesive strength of wood/PVC is discussed in detail.There are many factors that affect the adhesive strength of the adhesive,including factors such as polymer structure,adhesive composition,and bonding process.This subject uses ¹H-NMR,FTIR,GPC,SEM,tensile testing machine and rotary viscometer and other experimental equipment and acid-base titration and other experimental methods to characterize the structure of the graft copolymer,including molecular weight and molecular weight distribution,chain structure,chlorine content,The grafting rate,etc.,established the dependence of the structure and adhesion strength and other properties;at the same time,the influence of the proportion of tetrahydrofuran in the solvent,solid content,SiO₂ parts,etc.on the adhesive performance of the adhesive was also discussed.Based on the above experimental results,increasing the ratio of tetrahydrofuran will significantly improve the adhesive fluidity and thus the bonding strength;properly increasing the chlorine content and the grafting rate will also significantly improve the bonding strength;the solid content of the adhesive is about 12%,the release agent When the amount of SiO₂is about 12 parts,and the temperature of the non-pressed plate is 110℃,the bonding strength of the bonding plate is the best.Finally,in order to facilitate industrial implementation,a more detailed study of blended adhesives was carried out.The industrialized and readily available CPVC and monomer methyl methacrylate（MMA）are used for in-situ polymerization to form a sea-island structure,and the two-phase polymers interpenetrate at the phase interface to achieve a high adhesion effect.The preparation of blended adhesives mainly explores the preparation process,demonstrates the feasibility of the preparation process,and preliminary characterizes the aggregate structure of the product and its structural changes following the influencing factors.The content of this part is mainly to explore its laws and put forward opinions.