Study On Preparation And Properties Of Plant Fiber/PP Composites

In recent years,the use of natural renewable resources to develop environmentally friendly composite materials has become the focus of attention and research by Chinese and foreign scholars.Compared with traditional reinforcing fibers(glass fiber,etc.),natural plant fibers have a wide range of sources,low prices,high modulus,and renewable degradation.Natural fibers have poor compatibility with non-polar polymers,and direct processing will result in poor mechanical properties.Therefore,the research on improving the compatibility of natural fibers and polymers and toughening natural fiber/polymer composites has high application value.In this paper,the non-toxic renewable solvent?-valerolactone(GVL)was used to remove impurities from jute fiber.Observe the changes of fiber surface morphology and aspect ratio by SEM,and select the blending modification of jute and PP soaked at140°C for 1 hour.Toughening modification of jute/PP composites using tung oil anhydride(TOA),epoxy soybean oil(ESO)and TOA/ESO gels;the heat of TOA,ESO and TOA/ESO gels on jute/PP composites The effects of stability,crystallization,dynamic mechanics,micro-morphology and rheological properties;focus on the mechanical properties of jute fiber/PP composites treated by GVL and the TOA,ESO and TOA/ESO gels on jute fiber/PP composite The toughening effect of TOA,ESO and TOA/ESO gel toughening mechanism is analyzed.The conclusions are as follows:(1)After adding untreated jute fiber and PP blended to modify the mechanical properties of the composite material decreased,fiber and PP compatibility is poor,serious debonding phenomenon.After the GVL solvent treatment,the fiber impurities are removed,the fiber surface is rough and a large number of grooves are formed,the length-to-diameter ratio is increased,the fiber and PP are blended and modified,and the compatibility is good,and the fiber plays a good role in strengthening;The tensile strength of the jute composite material treated with GVL solvent increased from 38.3MPa to 43.4 MPa,the bending strength increased from 32 MPa to 44.5 MPa,and the tensile modulus increased from 408 MPa to 1365 MPa.After adding TOA to the Jute(GVL)/PP composite,infrared spectroscopy showed that the TOA anhydride group reacted with the fiber hydroxyl group.SEM shows that the compatibility of fiber and PP is improved,the compatibility and toughness of the composite material are improved,the elongation at break increases from 12%to 103%,and the impact strength is also increased by 3 times.In addition,TOA improves the thermal stability and crystallinity of the composite material,the glass transition temperature shifts to a low temperature,and the melt viscosity of the composite decreases.(2)Carboxyl groups are grafted on the fiber surface by chemical modification.The melt blending reaction of carboxyl groups and ESO forms an ESO layer on the jute surface,which improves the compatibility of fiber and PP.ESO significantly improved the toughness of jute fiber/PP composites,impact strength increased by12.4KJ/m~2,increased by 5 times,elongation at break increased from 14%to 225%,increased by 15 times,showing excellent toughening.ESO causes the crystallinity of jute fiber/PP composite to increase first and then decrease,the glass transition temperature shifts to low temperature,and the melt viscosity decreases first and then increases with the increase of ESO.(3)The TOA/ESO molar ratio Z value was designed to prepare TOA/ESO gel,and the gel structure change was analyzed by infrared.The gel added with ESO network structure in jute/PP composite material showed good toughening effect,in which the elongation at break increased from 13%to 66%,an increase of 5 times,the impact strength reached 12.5KJ/m~2,an increase of 4 times.The gel of the ESO network structure helps to improve the thermal stability of the composite material,reduce the crystallization temperature of the composite material and increase the crystallinity.The microscopic morphology of the gel shows that the gel has good compatibility with the matrix.After the impact,no debonding occurs.The addition of the gel increases the melt viscosity of the composite.