Research On The Properties Of Ferulic Acid Based Unsaturated Resin System And Its Composites

Unsaturated polyester resin refers to a class of polyesters containing unsaturated double bonds in the main chain of the molecule,and is generally prepared by adding an appropriate amount of vinyl monomer to the unsaturated polyester prepolymer.Commercially available unsaturated polyester resins(UPR)are prepared by mixing unsaturated polyester prepolymers(UPP)and Styrene diluents.They are widely used,but Styrene has been concerned for its shortcomings such as high volatility,carcinogenicity and the non-renewable resource.In addition,the polyester prepolymers that come from petrochemical engineering are not suitable for the sustainable society.In the first part of this thesis,Ferulic acid(FA)was used as the biomass material to synthesize a reactive diluent to replace Styrene.The reactive diluent,4-acetoxy-3-methoxystyrene(AC4VG),was synthesized by two steps:decarboxylation and acetylation.On the other hand,five monomers,Fumaric acid(FU),Propylene glycol(PG),1,3-propylene glycol(PD),Itaconic acid(IA)and Succinic acid(SA),were used to polymerize fully bio-based UPPS at a fixed hydroxyl/acid group ratio of 1.2:1.After dissolutions of the bio-based UPPs using AC4VG,rheological optimization was performed on the AC4VG mixture solutions.As a result,PISD UPP,which was synthesized from IA,SA and PD,was selected as a fully bio-based UPR for further researches.The resin has a viscosity of 2.11 Pa·s at room temperature and 0.11 Pa·s at 80?,indicating that the resin has excellent processability.When the UPR was composited using cotton fabrics as reinforced material,the obtained composites show excellent thermodynamic properties.Its glass transition temperature(Tg)reaches to 135?,thermal decomposition temperature(Td5%)to 223?,and the tensile strength to 63 MPa.In the context of the results,to further improve the tensile strength and heat-resistance of the composite material,the second part of this thesis demonstrated a new UPP that polymerized using four monomers:isosorbide(ISO),ethylene glycol(EG),oxalic acid(OA),and IA,and named as PIOSE.When the PIOSE UPP was mixed with AC4VG to prepare UPR,and was further composited with cotton fabrics,the resulting composites revealed remarkably improved mechanical properties and thermodynamic properties by comparing with that observed in the previous work.It is tested by a dynamic thermomechanical analyzer,a thermogravimetric analyzer,and a universal tensile tester.Its tensile strength is close to 80 MPa,the glass transition temperature(Tg)can reach 131?,and the thermal decomposition temperature(Td5%)higher than 320?.