Preparation And Characterization Of Flame Retardant Building Composite Insulation Materials

Building energy consumption is huge in China, implementation of building energy efficiency is imperative. Wall insulation technology is the main way of building energy efficiency and thermal insulation materials is the key factors. At present organic insulation materials were applied widely in domestic and these materials were inflammable. While thermal conductivity and dry density of inorganic insulation materials was too big can’t meet the requirement of the energy efficiency. And composite insulation materials can meet the insulation requirements and reach Class A non-combustible level.Lightweight aggregates, inorganic cementitious materials and additives were selected and preparation of composite insulation materials was studied. Results showed that EPS surface treatment improved hydrophilic, compressive strength and tensile strength were increased by 31% and 57%, respectively. Mechanical strength was higher and thermal conductivity was lower with well-graded EPS particles. Cenosphere volume content in lightweight aggregates volume was 30%, properties of the insulation materials meet standard requirement. Inorganic cementitious materials cement, fly ash and silica fume optimal content were 35%, 22% and 16%, respectively. Tensile strength was enhanced after adding re-dispersible emulsion powder, polypropylene fiber, and hydrophobicity was enhanced after adding silicone water-proofing agent, optimal content of powder, PP fiber, and water-proofing agent were 3.5%, 0.25% and 10%, respectively. Cone calorimeter teat results showed taht THR of insulation materials used lightweight aggregates of mixed surface treatment EPS particles and cenosphere was 0.7 MJ/m2, which had reached class A1 non-combustible level, and amount of smoke was smallest. Orthogonal test were designed and results showed that the optimum ratio of lightweight aggregate, fly ash, silica fume and fiber were 10%, 22%, 16% and 0.25%. Under this optimum ratio dry density was 224 kg/m3, thermal conductivity was 0.052 W/(m·K), compressive strength was 0.41 MPa, tensile strength was 0.26 MPa, water absorption capacity was 763 g/m2, softening coefficient was 0.92 and reached class A1 non-combustible level.Mechanism of raw materials was analyzed. The results showed that: major ingredient of powder is vinyl acetate/ethylene copolymer(EVA), nonpolar segments in EVA main chain absorbed to EPS surface, polar groups-OCCH3 of side chains and-OH of emulsion particle surface arranged outwards so that hydrophilic of EPS particles surface were increased. Clinker of sulphoaluminate cement reacts with water rapidly and reaction products were calcium silicate hydrate(C-S-H) gel and ettringite(AFt), volcano ash effect of fly ash and silica fume stimulated with hydration reaction of cement. Powder formed a layer of polymer film in inorganic substrate improved the crack resistance. Polypropylene fibers distributed randomly to a three-dimensional network structure in the inorganic substrate, which enhanced tensile strength significantly. But excessive content of fiber accumulated to a weakness point. Group of-H and-OH on silicone resin was combined with-OH and water on inorganic substrate surface. Hydrophobic group of Si-R was at terminal, which make the inorganic substrate hydrophobic. Diameter of pore in insulation materials is small and most are closed, so that the insulation material has excellent insulation properties.Aging test of insulation materials were investigated and the results showed that: insulation materials didn’t appear seepage, pulverization after freezing-thawing test and mechanical strength still meet the standards requirement, part interface between organic and inorganic were separated and cracks were appeared in inorganic matrix, so the thermal conductivity were increased; compressive strength and tensile strength of insulation materials were reduced slightly after wetting-drying test, the closed pore structure of EPS particles were destroyed led to the increase of thermal conductivity. Weight and area of insulation materials were increased slightly after hydrothermal accelerated aging test and mechanical strength still meet the standards requirement after 32 d aging teat.Insulation layer economic thickness were analyzed and calculated by Life Cycle Cost Analysis, the results showed that life cycle total cost firstly decreased and then increased with the increase of insulation layer thickness. Optimum economical thickness was 58 mm after calculated. Life cycle total cost was minimum and economic payback period was 5.8 years with this thickness.