Synthesis And Properties Of Ethyl Cellulose-Rosin Copolymer

Recently,the utilization of biomass resources to prepare polymer materials has attached more and more attention.Cellulose and rosin as the most abundant renewable resource with the characteristics of environmental friendliness,abundant reserves,and degradability,have been widely used to prepare various functional polymer materials.In order to further realize the high-value utilization of cellulose and rosin,in this paper a series of cellulose-rosin graft copolymers derived from cellulose,rosin and grease were prepared through esterification,step-growth polymerization and click chemistry,and inveatigated its application as a curing agent and UV-absorbing coating.A class of bio-based hybrid membrane EC-g-MPA-ESO was prepared by the esterification between the epoxidized soybean oil(ESO)and ethyl cellulose-rosin-based polymer(EC-g-MPA),which was synthesized by grafting rosin derivative maleopimaric acid(MPA)onto the ethyl cellulose(EC)backbone via esterification reaction.The chemical structure of EC-g-MPA was confirmed by FT-IR,¹H NMR,and UV-Vis spectrophotometer,demonstrating the successful preparation of EC-g-MPA.DSC analysis indicated that the glass transition temperature(T_g)of the EC-g-MPA-ESO composite film was only 15?which was caused by the internal plasticization of epoxy soybean oil,and indicating the composite film with excellent toughness.Mechanical property tests showed that when ESO content was 20%,the blend film shows the best mechanical properties,and tensile strength reaches the maximum value of 12.1 MPa.Cyclic tensile test showed the elastic recovery value of the composite membrane could reach 54.6%at80%strain,indicating the EC-g-MPA-ESO had a certain elastomer behavior,whcih can be used as a thermoplastic elastomer.At the same time,UV absorption performance studies showed that the composite film also exhibited excellent UV absorption characteristics due to the introduction of rosin,which had great application in UV absorption and degradable film materials.The ethyl cellulose maleate(EC-g-MPA)was acted as acid anhydride epoxy resin curing agent.Then,a series of epoxy resin polymers were prepared via curing between EC-g-MPA and grease based epoxy resin.FT-IR was carried out to confirm the chemical structure of the products.And non-isothermal DSC was carried out to investigate the curing kinetics of the curing system,and the results show the activation energy of the curing system was 73.94 kJ/mol,the pre-factor A of the curing system was 1.27×10⁶ s^-1,and the reaction order was 0.9,indicating the curing reaction is a complex process.The thermodynamic performance study shows the glass transition temperature of the product gradually increases with the increasing of EC-g-MPA content,and the cured resin also has excellent thermal stability.Mechanical properties study shows that the mechanical strength of the cured product increased with the increasing of EC-g-MPA content,and we could prepare the epoxy resins with different mechanical properties by adjusting the content of the curing agent.This curing agent could be used as a new type of biomass-based acid anhydride epoxy curing agent,and could be used to replace or partially replace petroleum-based curing agents.A class of sustainable UV-absorbent copolymers derived from ethyl cellulose(EC),fatty acid and rosin by combination of ATRP and“click”chemistry.During the preparing process,the pendent azides were firstly attached onto the backbone of EC.Then,ATRP was applied to fabricate well-defined poly(lauryl methacrylate)(PLMA)bearing terminal alkynes.Finally,the“click”chemistry between the pendent azides in EC and the alkynes in PLMA as well as in rosin esters(DAPE),was performed to achieve the cellulose-rosin graft copolymers(EC-(g-DAPE)-g-PLMA).The chemical structure of EC-(g-DAPE)-g-PLMA was confirmed by FT-IR,¹H NMR and GPC.DSC tests showed that the cellulose-rosin graft copolymer had two independent thermal transitions,and TGA analysis indicated that the introduction of rosin and PLMA could greatly enhance the thermal stability of cellulose-rosin graft copolymers.Static contact angles study showed that these cellulose-rosin graft copolymers exhibited excellent hydrophobic properties.And due to the introduction of rosin,these EC-rosin graft copolymers exhibited excellent and stable UV absorption capability,and maintained outstanding UV absorption capability after continuous UV-irradiation for 1 h or being heated to 100? for 0.5 h.These cellulose-rosin graft copolymers showed a potential application in UV absorption materials.