Preparation And Performance Of Synthetic Paper Based On Polyethylene Waste

The production and consumption of plastics have increased sharply because of their light weight,low cost and chemical resistance.However,this also results in the generation of plastic waste.Treatment,recycling and recovery methods for plastic waste are expected to be economically and environmentally viable.The traditional handling methods for plastic waste are related to landfill,incineration,chemical recycling and mechanical recycling.Usually,landfill occupies large space,while incineration stimulates the growing emission of some harmful,greenhouse gases,e.g.NOx,SOx,COx,etc.Recycling is required to decrease the waste volume and reduce environmental issues.Consumption of traditional cellulose paper around the world currently leads to deforestation.In order to solve this problem,synthetic paper is fabricated as a special film from thermoplastic polymers,which accepts writing or printing like cellulose paper.It can meet the requirements for light weight and reveal good resistance to weather,acids,and corrosion.In our research,polyethylene wastes(ultrahigh molecular weight polyethylene UHMWPE,low-density polyethylene LDPE,and high-density polyethylene HDPE)were recycled and used as raw material to fabricate synthetic paper adopting thermally induced phase separation(TIPS)method.The surface morphology of synthetic paper was observed by scanning electron microscopy(SEM).And the corresponding application performance including whiteness,chemical resistance,thermal stability,tensile strength,and inkjet print were also detected respectively.Crystallization property of synthetic paper was studied by X-ray diffraction(XRD)and differential scanning calorimetry(DSC).The nonisothermal crystallization kinetics of blends under different cooling rates was studied using DSC technique and analyzed by different models.The main results are as follow:(1)Synthetic paper based on ultrahigh molecular weight polyethylene(UHMWPE)waste was successfully prepared by using TIPS method.Whiteness of the resulting synthetic paper was in the range from 70% to 90%.The tensile strength can reach up to 5.5 MPa when the Si O2 content was 20wt%.All samples have good adherence resulting in good printing effect.In addition,the synthetic papers have good resistance to chemical corrosion and reveal good shape maintenance.(2)Synthetic paper based on low-density polyethylene(LDPE)film waste was also successfully prepared by using TIPS method.The crystallinity of the resulting samples varied from 40% to 60%,and it decreased with the increase of LDPE content.Whiteness of the synthetic paper was above 90% except for the one with LDPE content in 50wt%.Tensile strength of the synthetic paper reached up to 6.0 MPa when the LDPE content was 50wt%.Moreover,the synthetic papers revealed good resistance to chemical corrosion and water.In addition,the samples also had excellent inkjet printing quality with clear images and vivid colors.(3)Synthetic paper used for printing was also successfully prepared from high-density polyethylene(HDPE)waste by using TIPS method.It shows that with the increase of cooling rate,the semi-crystalline time(t1/2)decreases,and the overall crystallization rate increases.It is found that the Avrami index n related to nonisothermal crystallization kinetics is close to 2 according to Jeziorny method.Mo approach rather than Ozawa approach can give the reasonable interpretation for the crystallization behavior.The resulting synthetic paper possess suitable ink receptivity and good whiteness(90%).The optimal Si O2 content is in the range from 20 wt% to 25 wt%.Moreover,the highest tensile strength is up to 7.67 MPa.As a result,UHMWPE,LDPE,and HDPE wastes are all expected to be recycled for preparing synthetic paper,which can meet some special requirements in different surroundings that cellulose paper is not applicable.