Research On Application Of Discarded Polystyrene Foam

Polystyrene has become an indispensable part of people's daily life,and many of its excellent properties can't be replaced by other polymer materials.Handling a large number of discarded polystyrene materials has become a tough environmental issue.Discarded polystyrene foamed plastic is a very stable material,and it is not easy to degrade or decompose.So it can pollute the environment easily.Meanwhile,as the product of non-renewable resources,it is a huge waste to be discarded after a single use.Recycling is one of the best solutions to solve this problem.Therefore,the disposal and recycling of waste plastic foam is being taken seriously at home and abroad.A large number of in-depth researches on these issues are focused on(1)preparation of construction materials;(2)preparation of modified flame retardants of brominated;(3)cleaved into monomers or oil products;(4)recover thermal energy by burning;(5)preparation of adhesives and coatings.Turning waste into treasure is a good way of recycling resources.This is not only better for economic efficiency but also good to control environmental pollution.Both of them have a positive social significance.The contents of this thesis consists of two parts:(1)preparation of solvent-based adhesive;(2)preparation of chemically graft modified waterproof coating.In the preparation of the adhesive,the thesis systematically discussed how the mixed solvent,tackifying resin(rosin,pentaerythritol ester of rosin modified and petroleum resin)and toughening modifier(SBS)effect the properties of adhesive.Polystyrene is non-polar high molecular substance.Its molecular structure contains a rigid benzene ring.Its flexibility is poor and it is very brittle.It has a poor adhesion on the surface of wood,metal,paper and other polar substance.Therefore,it must be modified with a polar resin in order to enhance its adhesion.Through single factor experiment,the best ratio of modified PS adhesive is determined:m(PS):m(rosin):m(SBS)was 85:3:12.In this case,the shear strength(6.60 MPa)of wood was relatively larger.Various performance indicators of modified PS adhesive,such as adhesive bonding shear strength,solid content,heat aging resistance and thermal stability(TG and DSC)were tested.Changes in functional groups was observed before and after aging of adhesive films by infrared spectrum analysis.Microtopography was observed before and after aging of adhesive films by scanning electron microscopy.This adhesives show a very good overall performance and it is suitable for bonding of wood,tile,metal,paper and other products.In the preparation of graft modified waterproof coatings,firstly,PS graft copolymers are prepared by solution grafting and process conditions of the grafting onto PS with acrylic acid and butyl acrylate in the medium of ethyl acetate-cyclohexane was discussed.The best reaction conditions is concluded by orthogonal experiment:the amount of initiator(2.2%),the amount of monomer(20%),V(acrylic acid):V(butyl acrylate)was 3:2,the reaction temperature(85?),the reaction time(2.5 h).Different factors' effect on the grafting yield is concluded by range analysis:the amount of initiator>the reaction temperature>the reaction time>the amount of monomer>V(acrylic acid):V(butyl acrylate).Comparing the IR spectrum of unmodified PS with the IR spectrum of graft modified PS,it can be confirmed that acrylic acid and butyl acrylate has been successfully grafted onto the PS backbone.Secondly,the influence of emulsifiers,water-oil ratio,emulsification time and the amount of stabilizing agent on the properties of emulsions was studied.As the overall performance(such as film formability,stability and viscosity,etc.)of the emulsion as a standard,the best reaction conditions is concluded by orthogonal experiment:grafted PS solution(100%),the amount of emulsifier(4.0%),water-oil ratio(1:1),emulsification time(2 h),the amount of stabilizing agent(0.75%).Finally,the effect of the modified PS emulsions,plasticizers and fillers on the performance of waterproof coatings was studied.The formulations of modified PS waterproof coating was obtained by experiment:PS emulsion(100%),plasticizer(4%),fillers(15%),appropriate amount of defoamers.This coating production costs low and its water resistance is good.Furthermore,it has an advantage of simple preparation process and simple construction.It can be used in waterproof of corrugated boxes,fiberboard and wood.It can play a role in moisture-proof and airtight.