Study On Preparation And Application Properties Of Composite Silk Board Of Cornstalk

In order to solve the waste of cornstalk resources,poor wettability and low internal bond strength of cornstalk composites,in this study,the cornstalk was used as the experimental material,the microstructure of cornstalk was observed,the elemental composition of skin and pith were analyzed,then the cornstalk was eased into filamentous structures,urea formaldehyde resin and isocyanate were used as adhesive respectively,these filamentous structures were used to fabricate the composite by different formation mode of orientation and non-orientation.The effects of pavement structure,resin content and length-thick ratio on the properties of cornstalk composites were studied.This study laid the foundation for the study of the light weight wall material of cornstalk.The main results and conclusions are as follows:(1)The initial contact angle of the outer surface of cornstalk was significantly higher than that of the inner surface,and the contact angle of the outer surface unchanged with the time,the content of Si on the outer surface is high and evenly distributed.There is a big difference between the inner and outer surface of wettability.(2)The physical and mechanical properties were improved by orientional formation.Under the same density,the modulus of longitudinal rupture(MOR//),modulus of longitudinal elasticity(MOE//)and internal bond strength(IB)of the orientional composite silk board of cornstalk which used urea-formaldehyde resin adhesive(OCSB)were higher than that of homogeneous composite silk board of cornstalk(HCSB).The MOR//and MOE//values of OCSB were about 3 times,and the IB value was about 4-5 times,as much as HCSB with the same density.In addition,the water absorption(WA)and thickness swelling(TS)of OCSB were smaller than HCSB.(3)Compared with the OCSB,the water resistance and mechanical strength of the orientional composite silk board of cornstalk which used isocyanate adhesive(MOCSB)were obviously improved.The TS of the MOCSB which the resin content is 5%and the density is 0.6 g/cm3 decreased by 60%compared to OCSB,the MOR//increased about 1 times and the IB increased about 2 times.(4)With the increase of density,the thermal resistance of MOCSB decreased and the thermal conductivity(TC)increased,the resin content had a little influence on heat conducting performance of the MOCSB,TC of the MOCSB under all experimental conditions were less than 0.12 W/(m K),which satisfied the requirements of thermal insulation materials.Noise reduction coefficient of all MOCSB was 0.44 to 0.51,which was greater than the minimum standard of 0.2 of sound-absorbing material.The composite silk board of cornstalk which were prepared with cornstalk have fine mechanical and sound thermal properties,and it can meet the requirements of the building sound-absorbing insulation composites.(5)The MOR and MOE of composite silk board of cornstalk were improved with the increase of the ratio of the length of the structural unit and the thickness of the composites,When the the ratio of length to thickness is 2,the IB of the composite silk board of cornstalk is obviously better than that of 3 and 4.