Properties And Manufacturing Technology Of Particleboard Made From Alkaline Treated Wheat Straw

In this paper,wheat straw particle was chosen as the research object and made wheat straw particleboard bonded with isocyanate binder(PMDI),the manufacturing technology of particleboard and the effect of variables factors on properties of board was investigated.The wheat straw particles were treated by Sodium hydroxide(NaOH)and ammonia hydroxide(NH3·H2O)solutions and the wettability,chemical properties,pyrolysis properties and crystallinity were investigated.The properties of particleboard made from the treated particles were also investigated to evaluate the effect of alkaline solutions treatment.The main conclusions are as follows:(1)Results of the response surface design indicated that hot-pressing temperature(HT),density(ND)and resin content(RC)had significant impact on physical and mechanical properties of particleboard.For modulus of rupture(MOR),modulus of elasticity(MOE)and internal bond strength(IB),the range was ND>RC>HT.For thickness swelling in 2h(2hTS),the order was RC>ND>HT.(2)The optimized manufacturing technology parameters in this research was RC:4.6,.ND:0.80 g/cm3,HT:177 ?.(3)The wettability of alkaline solution treated wheat straw was improved and the waxy layer was partly removed.Additionally,the mass residue rate and crystallinity of wheat straw was also increased.(4)MOR and MOE of both solutions were improved.MOR was significantly improved by NaOH solution and MOE was significantly improved by NH3·H2O solution.The internal bond(IB)strength of NaOH-treated board but IB of NH3·H2O solution treated and the 24 hTS of all the specimens in this experiment were not improved or even worse.(5)Mechanical and physical properties of board made from alkaline solution treated wheat straw were improved after sprayed with magnesium chloride(MgCl2)solution.