Preparation Of Polyvinyl Butyral(PVB)

Polyvinyl butyral is a polymer compound(PVB)produced by the condensation reaction of polyvinyl alcohol(PVA)and n-butyraldehyde under acidic conditions.Because its molecular chain contains acetal,hydroxyl and a certain amount of ester groups.Therefore,the pressed film has a certain strength;it has high adhesion to metals and glass(especially aluminum)and has a certain degree of flexibility.This paper studies the main factors affecting the acetalization rate,hydroxyl value,and bulk density from three aspects.The experimental results show:(1)The reaction temperature,reaction time and acidity of the system are the main factors affecting the acetalization rate.When the reaction time is 7 to 8 hours,the reaction termination temperature is 60?65?,and the acidity of the reaction system is 0.5?0.6%,the acetalization rate of PVB reaches the best range: 78?80%.(2)The reaction temperature,reaction time and acidity of the system are the main factors affecting the acetalization rate.When the reaction time is 6.5?7.5 h,the reaction termination temperature is 60?65?,and the acidity of the reaction system is 0.4?0.6%,the hydroxyl value of PVB reaches the best range: 18.5%?19.5%.(3)Reaction time,reaction temperature and holding time are the main factors affecting the bulk density of PVB.When the reaction time is 6.5?7.5h,the reaction termination temperature is 50?55?,and the bulk density of PVB reaches the best range when the holding time is 50?80min: 23.5?24.3(g/ml)(4)The compounding of multiple antioxidants can improve the thermal stability of PVB.By comparing a single antioxidant with a compounded antioxidant,it is concluded that the thermal stability of PVB with a compounded antioxidant is significantly better than that with PVB with a single antioxidant,and when the compounded antioxidant 1178,The thermal stability of PVB was best when 452 and 3g were added respectively...