Preparation And Properties Of Bamboo Powder/mica/polypropylene Composites

Polypropylene?PP?has the advantages of low density,low price and easy to process.And its application field is extensive.However,the disadvantages of low temperature brittleness,poor resistance and difficult degradation limit its use.Therefore,in order to improve the comprehensive performance of PP,the filling modification of PP has become the research focus of PP composite materials.Compared with inorganic fillers,natural plant fiber has the advantages of light weight,low price and reproducibility,which is highly valued in the research field of new composite materials.Among them,bamboo powder?BF?,as a kind of natural plant fiber with shorter growth cycle and better plasticity,is expected to be an organic filler for replacing wood.At the same time,mica,as a kind of inorganic filler of silicon oxide tetrahedral sheet structure,has the advantages of high chemical stability and weatherability.Therefore,adding a small amount of mica to bamboo powder/PP composites can effectively improve the toughness of bamboo powder/PP composites.This paper studies the preparation and properties of modified bamboo powder and modified mica,main purpose is to both filled into PP matrix,preparation of performance by melt extrusion bamboo powder/mica/polypropylene composite material,and the relationship between material performance and structure is studied systematically.The details are as follows:The bamboo powder was treated by 2 wt%NaOH,and its surface was changed from smooth to rough,the structure of the skeleton was intact,and the thermal stability was increased.The secondary modification of bamboo powder was by silane coupling agent,when the mass fraction of the silane coupling agent KH550,KH560 and KH570 was 3%,6%and7%,respectively,modified bamboo powder has the largest activation index and lowest polarity.The mechanical properties of bamboo powder/PP composites were optimized when the mass fraction of modified bamboo powder(BF_2-55?BF_2-56-56 or BF_2-57)was 35%,its tensile strength and bending strength were 39.43⁴2.5 MPa and 58.3⁶0.0 MPa,respectively,which increased by 11.5²0.2%and 41.2⁴5.3%,respectively,compared with that of pure PP.However,the impact strength is limited to 5.1⁶.1 kJ.m^-2.The mechanical properties of the composite materials prepared by using silane coupling agent KH550 for secondary modified bamboo powder into PP(PP/BF_2-55)were optimized.By adding modified bamboo powder,the lattice size of PP was refined,and the crystallinity of the material was increased.The crystallinity of PP/BF_2-55-55 was increased by 13.06%compared with that of pure PP.The thermal deformation temperature of the composite was improved,and the vika softening point of PP/BF_2-55-55 was higher 8.7?than that of pure PP.The prepared composite materials meet the standard requirements of the water absorption rate of the wood plastic industry,and the materials have good waterproof properties.The activated mica was obtained by treated with dodecyl trimethylammonium chloride?DTAC?for intercalation after being heating,acidification and natrification.When the intercalation reaction is carried out under 80?for 24 h,the mica has the largest dispersion and the lowest polarity.The mica layer was thickened after the interlayer modification,the surface was slightly roughened,most DTAC existed in the mica layer and a few DTAC existed on mica surface.It was used to fill PP with 35%modified bamboo powder and 5%modified mica to prepare the composite material of bamboo powder/mica/PP(PP/BF_2-55/M_C3),the impact strength was significantly improved compared with that of bamboo powder/PP composites(PP/BF_2-55).The tensile strength,bending strength and impact strength of PP/BF_2-55/M_C33 were 43.98 MPa,68.33 MPa and 10.70 kJ.m^-2,respectively,which increased by 24.7%,65.4%and 162.3%,respectively,compared with that of pure PP.The vika softening point of PP/BF_2-55/M_C33 was higher 10.1?than that of pure PP.At the same time,the addition of mica is beneficial to the crystallization of PP matrix,the crystallization temperature?T_p?of PP/BF_2-55/M_C33 composites was higher 2.1?than that of pure PP,the super-cooling degree?T was lower 3.9?than that of pure PP.