基于原位聚合的涤麻混纺织物/PAA复合材料的制备及性能OA

Natural fiber-reinforced polymer composites have attracted considerable attention because of their low density,renewability,biodegradability,and favorable specific mechanical properties.Polyester-hemp blended fabrics are particularly promising as reinforcing materials because they combine the strength and dimensional stability of polyester with the stiffness and renewable characteristics of hemp.However,conventional resin impregnation methods usually suffer from high resin viscosity,insufficient penetration into the fabric structure,and weak interfacial adhesion,which limit the mechanical performance of the resulting composites.In this work,a one-step preparation strategy combining in-situ free-radical polymerization with hot pressing was proposed to fabricate polyester-hemp blended fabric/poly(acrylic acid)(PAA)composites.The main purpose was to replace high-viscosity prepolymer impregnation with low-viscosity monomer infiltration,so as to improve impregnation efficiency and fiber-matrix interfacial bonding. A plain polyester-hemp blended fabric with a polyester/hemp ratio of 7/3 was used as the reinforcement.Acrylic acid(AA)was selected as the monomer,potassium persulfate(KPS)as the initiator,and N,N-methylenebisacrylamide(MBA)as the crosslinking agent.The fabric was immersed in the reaction solution,and the in-situ polymerization process was carried out under water-bath heating.After drying,the prepreg was consolidated by hot pressing to obtain the final composite.The effects of monomer concentration,polymerization time,and polymerization temperature on the mechanical properties were investigated by a single-factor method.The results showed that the optimal polymerization parameters were an AA volume fraction of 8％(v/v),a polymerization temperature of 80℃,and a polymerization time of 1.5 h.Under these conditions,the composite exhibited the best overall balance of strength,stiffness,and ductility. The optimized composite showed significantly improved tensile properties compared with the original polyester-hemp blended fabric.Its tensile strength,elongation at break,and tensile modulus reached 83.50 MPa,9.42％,and 936.46 MPa,respectively,whereas the original fabric showed corresponding values of 21.02 MPa,10.6％,and 249.35 MPa.The tensile strength and modulus of the composite were therefore about four times those of the fabric,indicating that the proposed process effectively enhanced the load-bearing capacity and stiffness of the material while maintaining acceptable elongation.The tensile curve also suggested a deformation process involving elastic deformation,plastic deformation,and final fracture,indicating that the composite still retained a certain degree of toughness after matrix introduction. The strengthening mechanism was analyzed by combining microscopic and structural characterization.SEM observations of the fracture surface showed that the PAA matrix effectively bonded polyester and hemp fibers into an integrated structure,and polymer residues remained attached to the exposed fiber surfaces after fracture.FTIR results showed obvious changes in the O-H stretching region and the C=O absorption region,suggesting the existence of strong intermolecular interactions,especially hydrogen bonding,between the carboxyl groups of PAA and the hydroxyl groups on hemp fiber surfaces.These interactions contributed to improved interfacial adhesion and more efficient stress transfer.XRD analysis revealed that no new crystalline peaks appeared after composite formation,while the characteristic peaks of the fabric remained but with reduced relative intensity,indicating that PAA mainly existed as an amorphous phase and coated the fibers during hot pressing.TG and DTG results further confirmed the successful formation of the composite and reflected the different thermal degradation behaviors of PAA,hemp,and polyester components. In summary,the combination of in-situ free-radical polymerization and hot pressing provides an effective route for preparing polyester-hemp blended fabric/PAA composites.This method avoids the impregnation difficulties associated with high-viscosity resins,improves the fiber-matrix interfacial structure,and significantly enhances tensile strength and modulus.The study provides an experimental basis for the development of high-performance and environmentally friendly cellulose-based textile composites,and also offers a useful strategy for interface design in fabric-reinforced composite materials.