| Crop straw is a natural biomass material and is commonly used for land filling or is burned,resulting in environmental issues.Therefore,to fully exploit the a large amount of bioresource crop straw.In this thesis,wheat straw(WS)with surface alkali liquor processing was used as raw material to prepare ionic liquid-type glueless biomass board([PWS-IDA][Cl])under the condition of hot pressing by grafting imidazole-4,5-dicarboxylic acid(IDA)and allyl chloride.The board not only can be applied to building materials,but also solves the problem of flammability of the board.The main contents and conclusions were given as follows:(1)To analyze the mid product of ionic liquid-type materials,the crystallinity and functional groups of the materials were characterized by the X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR).The results showed that the intermediate product synthesized by this method is reasonable.Scan the morphology and structure of the alkali pretreatment of wheat straw(PWS)and [PWS-IDA][Cl]materials before and after combustion by scanning electron microscopy(SEM),The results confirmed: the formation of compact and dense structure for ionic liquid type material,which could obstruct the spread of heat and mass,and thus improved the heat stability and flame retardancy of [PWS-IDA][Cl] materials.(2)The flame-retardant properties of the two types of materials were tested with an alcohol lamp,UL-94 vertical combustion meter,and limiting oxygen index meter.the result showed: Introduction of ionic liquid can significantly improve the flame retardancy as well as dimensional stability of WS materials,which could effectively prevent the collapse and destruction of material structures.Compared with the PWS,the limited oxygen index of [PWS-IDA][Cl] materials(15%)was increased from 21%to 32% and its UL-94 reached V-0 rating.(3)The universal testing machine was used to test the tensile and bending properties of the two materials,and the mechanical analysis showed: the maximum tensile strength of 8.525 MPa and the maximum flexural strength of 3.650 MPa for PWS materials.Meanwhile,the addition of ionic liquid increases the tensile and flexural strength of the material to 14.800 MPa and 8.500 MPa,respectively. |
