Study On The Properties And Corner Connection Of Wood Fiber/High Density Polyethylene Composite Window Profile

As a new environmentally friendly material,wood-plastic composite(WPC)can be widely used in the production of doors and windows,but there are some problems in the detection and corner connection of window profiles.This thesis focused on the corner connection technology of WPC window profiles by using bonding,welding and composite connection three ways.The influences of the formulations,treatment conditions and connection types on the corner strength of WPC window profiles were also studied.(1)The properties of WPC casement window profile which contain 50/60/70 parts wood flour were investigated,the results showed that other properties all satisfied the use requirement of PVC profiles except the drop-hammer impact.The mechanical properties of three kinds of wood flour content WPC profiles were tested.The results showed that the tensile materials,flexural and impact strength were maximum when the wood flour content was 60 parts;and the tensile modulus and flexural modulus were increased with the increasing of the wood flour content.(2)Bonding:The influences of the wood flour content and treatment conditions on the corner strength of WPC window profiles were studied which bonded by epoxy resin and moisture curing polyurethane hot melt adhesive.Bonding corner bending stress was tested by the angular intensity detector,which investigated by the contact angle,surface roughness and ATR-FTIR.The results showed that:(a)after silane coupling agent and plasma treatment,the corner bending stress of WPC profiles bonded with epoxy resin was increased nearly double.When the wood flour content was 70 parts,the post-processing of the corners bending stress was maximum up to 10.93MPa;(b)after isocyanic acid ester coupling agent and plasma treatment,the corner bending stress of WPC profiles bonded with moisture-curable polyurethane hot melt adhesive was significantly increased.When the wood flour content was 60 parts,the post-processing of corners bending stress was maximum up to 10.12MPa;(c)After plasma treatment,the contact angle of WPC windows profiles surface significantly reduced and the surface roughness increased.And the non-polar group weakened and corners bending stress increased.(3)Welding:The influences of the formulations,technology and welding surface treatment on the corner strength of WPC window profiles were studied It was trial by strength testing and curling corner test,analyzed test results by using a rotational rheometer and summarized the welding performance factors.The results showed that:(a)with being from 50 parts to 70 parts of wood flour content,corners bending stress significantly reduced by welding connection;Filling the thermal insulation cavity of the window profile with HDPE could improve the corner bending stress to 22.40MPa.(b)when the welding pressure was 0.2MPa,t=75s,T=230?,corner bending stress was the maximum up to 17.94MPa,and curling size was 4.7 mm around.(4)Composite connection:bonding and welding WPC composite window profiles combined with the mechanical connection method,which were tested by the angular intensity detector.The results showed that:(a)when mechanical and bonding connection method were used,the corners bending stress results were similar to bonding strength;(b)when mechanical and welding connection method were used,the corners bending stress results were maximum,which was 20.47MPa.