| Interface between different materials in building composite material is a weak link, which affects the material properties significantly. By using scanning electron microscopy analysis, infrared spectroscopic analysis, thermal properties analysis, mechanical properties analysis and so on, the paper focuses on carrying out composite modification for interface of mycelium composite sheet and asphalt composite material, as well as cement-based composite materials. the following conclusions are obtained:(1) Add appropriate rice straw, longan shells, cotton seed hull and other agricultural leftovers in mushroom pack through several times of fruiting, or add appropriate starch and other nutrients as the binder, fill in mold trial for molding at about 100kPa. After molding and cover the surface with Cling film, placed in dark and damp room, then waiting, wait for germination and growth of mycelium again. And after mycelium growing and wrapping agricultural leftovers, dry the sample, demold and treat the surface with styrene butadiene latex and polyurethane coating materials, to obtain mycelium composite sheet. Prepared mycelium composite sheet features small volume and density, thermal conductivity coefficient of less than 0.06w/mk.(2) The type of binder and spawn has relative large effect on the properties of mycelium composite sheet. The studying results also show that there are little hairy fibers on cotton seed hull, which are connected to mycelium, with higher size stability and strength, more favorable for the preparation of mycelium composite sheet; Cha 39 mycelium is thick and bushy, which can cover the cotton seed hull and form good mycelium network, so the products have high specific strengths.(3) Add styrene butadiene latex of not more than 5% in culture medium, which not only has no influence on germination and growth of mycelium, but also forms dual network to wrap base material and fill pores in the binder, thus to play a certain bonding role, so the closer bonding of the binder improve the specific strength of mycelium composite sheet. 0.5% Silane coupling agent is sprayed on the surface of culture medium, which not only has no influence on germination and growth of mycelium in styrene butadiene latex mycelium composite sheet, but also further enhance the interfacial bonding between latex and the substrate, thus to improve the specific strength of composite sheet.(4) Add about 10% polyvinyl alcohol particles in culture medium, which has no influence on germination and growth of mycelium. When drying composite sheet, solid polyvinyl alcohol dissolved in water contained in the sheet, pores in the sheet will be filled by its dispersion, which covers the surface of the culture medium and mycelium, and new network system will be formed, thus the bonding with the binder and mycelium interface is enhanced, so sheet strength is improved.(5) Add about 1% glass fiber in culture medium, which can prevent the surface of mycelium composite sheet after drying from dropping broken bits, shrinking and deforming, and reduce 2h absorbent thickness expansion rate, and enhance bending strength and specific strength of the products. After treated by silane coupling agent, a coupling agent layer forms on glass fiber surface through chemical bonding, which prepares mycelium composite sheet by compositing polymer latex, and the interfacial bonding between glass fiber and latex is improved, the bonding with the binder and mycelium enhanced, and specific strength of the sheet increased. Among which bending strength of relative datum sheet of leftovers mycelium composite sheet of modified rice straw-based mushroom pack is increased by 135.8%, specific strength increased by 76.6%; compared with datum sheet, bending strength of relative datum sheet of leftovers mycelium composite sheet of modified cotton seed hull-based mushroom pack is increased by 99.7%, specific strength increased by 47.3%.(6) Interface modification is an important way to improve Strength of composite materials, the addition of different transition between the material composition can improve the bonding properties between them. After surface modification by coating aqueous solution of silane coupling agent KH-550, steel or cement mortar test-block interface will be sprayed emulsified asphalt as the middle interface layer,then be bonded with hot bitumen, Due to small surface tension of emulsified asphalt it can forms continuous covering film on specimen, thus to produce very strong adhesion, meanwhile it has good compatibility with the hot asphalt, so it can significantly improve the strength. After coated 0.6% aqueous solution of silane coupling agent KH-550 on the cement mortar test-block interface and then bonded with emulsified asphalt and hot asphalt, 28d tensile strength of the sample is increased by 208.8% than that of blank sample untreated and directly bonded with hot asphalt. And The steel after coated 0.6% aqueous solution of silane coupling agent KH-550 and then bonded with emulsified asphalt and hot asphalt, 28d tensile strength of the sample is increased by 50.0% than that of blank sample untreated and directly bonded with hot asphalt.(7) Add 0.2-1.5% silane coupling agent KH550 in ordinary cement mortar, styrene butadiene latex mortar in the mortar and concrete to carry out surface modification, two effects have been got. First, through interface modification, the bonding of cement mortar as well as bonding between latex, cement paste and aggregate is enhanced, with significantly improvement of cement mortar strength. Second, the coupling agent is adsorbed by the cement particles, thus promoting the dispersion of cement particles and improving the mobility and water retention of the mortar. Dosage of silane coupling agent KH550 is about 0.5%, which boasts of better effects in both aspects.(8)Infrared spectroscopic analysis shows that surface of mortar powder and steel fiber through coupling agent treatment forms a coupling layer, thus improving the mechanical properties of polymer mortar; silane oligomers can also react with hydroxyl on steel surface, thus effectively improving interfacial adhesion of steel fiber mortar and their polymer modified mortar and enhancing the mechanical properties. Steel fiber through 0.5% silane coupling agent treatment, bending strength of steel fiber (dosage of 1.5%) cement mortar is increased by 17.7%, benging strength of polymer steel fiber mortar is increased by 31.7%.This study in the paper is of importance for properties improvement and its promotion of mycelium composite sheet, which is new building composite material; meanwhile, it has instructive significance for improving traditional asphalt and cement-based composite building materials.
|
PDF Full Text Request