Study On Moulding Technology And Characteristics Of Corrugated Bamboo-mat Plywood

Corrugated bamboo-mat plywood is prepared by compression moulding of the bamboo-mat which was impregnated with adhesive.Using corrugated bamboo-mat plywood as wall sandwich material of the fabricated buildings,which is not only ensure the strength of the wall,but also save raw materials and reduce the weight of the wall.Therefore,corrugated bamboo-mat plywood has a good application prospect in areas such as building structural material in future.This paper mainly studied preparation technology of corrugated bamboo-mat plywood,and also studied the effects of moulding process parameters and mould parameters on the moulding characteristics of corrugated bamboo-mat plywood as well as the physical and mechanical properties of its composite structural materials.Moisture content,resin content and staking angle were investigated,and the physical and mechanical properties were characterized with the longitudinal bending,the maximum compressive load,the surface quality and the quantity of deformation.Further,the preparation parameters of corrugated bamboo-mat plywood were optimized.The influences of the mould-pressing parameters on physical and mechanical properties were evaluated systematically by the response surface method.The results indicate that the moisture content of the bamboo-mat,hot-press temperature and time show the insignificant effect on physical and mechanical properties and the better mould-pressing parameters are obtained.Corrugated bamboo-mat plywood was prepared by the different moulds,then the composite structural materials were produced by corrugated bamboo-mat plywood as sandwich layer and eucalyptus wood plywood as surface,moreover,the physical and mechanical properties of corrugated bamboo-mat plywood and composite structural materials by the different moulds were analyzed.The results are described as follows:(1)Moisture content and resin content of the bamboo-mat showed the significant effect on the physical and mechanical properties and insignificant effect on surface quality and the deformation of corrugated bamboo-mat plywood.Longitudinal bending and maximum compressive load reduced with increasing moisture content of the bamboo-mat.The entire performances of corrugated bamboo-mat plywood increased with increasing the resin content increasing,especially for longitudinal bending and maximum compressive load.Staking angle showed significant effect on surface quality and the deformation,but it showed insignificant effect on the mechanical properties of corrugated bamboo-mat plywood.On the whole,the better conditions for producing corrugated bamboo-mat plywood with favorable properties are 15 % of moisture content,15 % of resin content and 45° of staking angle.In this condition,longitudinal bending,maximum compressive load of the corrugated bamboo-mat plywood are 4390.91 N,81.8 N,and the surface quality is better.(2)In the analysis of response surface of moisture content of the bamboo-mat,hot-press temperature and time,within the ranges of mould-pressing parameters in this research,the corrugated bamboo-mat plywood showed excellent performance in many aspects.The better conditions for producing corrugated bamboo-mat plywood with favorable properties are 12 % of moisture content,145 ℃ of the hot-pressing temperature and 13 min of hot pressing time.In this condition,longitudinal bending,modulus of rupture(MOR),impact strength,maximum compressive load,surface quality,24 hTS and 24 h water absorption are 9419 N,179.3 MPa,32.63 KJ/m2,531.9 N,37.4 point,0.98 % and 11.52 % respectively.(3)Moulding parameters showed the significant effect on the longitudinal bending,MOR,impact strength and maximum compressive load.However,they showed the insignificant effect on 24 hTS and 24 h water absorption.The first group of corrugated bamboo-mat plywood(pitch of waves 100 mm,margin 20 mm)had the maximum longitudinal bending and the maximum pressure load,but their impact strength and MOR were minimum.The longitudinal bending,MOR,impact strength and maximum compressive load of the second group of corrugated bamboo-mat plywood(pitch of waves: 120 mm,margin :30 mm)showed the moddle values.In contrast to the first group products of corrugated bamboo-mat plywood,longitudinal bending force and maximum pressure load of the the third group of corrugated bamboo-mat plywood(pitch of waves 120 mm,margin 20 mm)were minimum,while the impact strength and MOR were the largest.Taken the three kinds of corrugated bamboo-mat plywood into consideration,it can be concluded that the physical and mechanical properties of the corrugated bamboo-mat plywood with pitch waves 120 mm and margin 30 mm(the second group products)were the best.(4)Composite structural materials were produced by corrugated bamboo-mat plywood as sandwich layer and eucalyptus wood plywood as surface.The influences of the mould parameters on the mechanical properties of composite structure parts were investigated.The results showed that the flush compressive strength of the specimens of composite structural materials composed of the corrugated bamboo-mat plywood with pitch waves 120 mm and margin 30 mm(the second group)was higher than those of the composite structural materials composed of the corrugated bamboo-mat plywood with pitch of waves 100 mm and margin 20 mm(the first group)and the third group products with pitch of waves 120 mm and margin 20 mm.Horizontal shear strength of the specimens was related to the number of wave in a certain length.The more the number of wave is,the higher horizontal shear strength is.The flush compressive strength of the composite was decided by the contact surface area between the sandwich layer and surface layer.The larger of gluing area is,the higher compressive strength is.Flush compressive strength of the composite structural materials were related to the obliquity of the bevel between the peaks and troughs,the smaller obliquity is contributed to the shaped capability of corrugated bamboo-mat plywood,and they are destroyed difficultly.Considering the mechanical properties of composite structural materials,it can be concluded that the second composite structural materials had a better performance.Composite structural materials with corrugated bamboo-mat plywood as the core layer is feasible to use in building structure and they are worthy of research in the future.