废弃EPS颗粒表面改性及其在地聚物基建筑外墙外保温材料中的应用

Surface Modification of Waste EPS Particles and Its Application in Geopolymer-based External Wall Thermal Insulation Materials

以偏高岭土地聚物为基体、废弃聚苯乙烯泡沫(EPS)颗粒为保温轻骨料,研发了一种无机-有机复合建筑外墙外保温材料。以抗压强度、抗折强度为指标,探讨了EPS颗粒的最佳改性条件;然后以抗压强度及和易性等为主要参考指标,确定了该保温材料的最佳配比。结果表明:当复合改性剂乳胶粉乳液(固含量40%)/三乙醇胺的配比为1/1(体积比)、体积分数为3%(相对于EPS颗粒),且EPS颗粒表面偏高岭土包裹量为EPS颗粒质量的4倍时,改性EPS颗粒与地聚物胶凝材料具有良好的亲合性;另外,当3种外加剂(纤维素醚、木质纤维和乳胶粉)的质量分数(相对于偏高岭土)分别为0.5%、0.6%和3%,改性EPS颗粒的体积分数为80%,水灰比为0.66时,该保温材料的各项性能指标基本达到国标JG 158—2004的要求,其干密度、抗压强度、吸水量、软化系数和导热系数分别为314 kg/m3、0.24 MPa、694 g/m2、0.875、0.065 W/(m K),材料难燃性达到B1级。

Using metakaolin-based geopolymer as matrix, and waste expanded polystyrene（EPS） particles as lightweight aggregate, a kind of inorganic-organic composite external wall thermal insulation material was developed. The optimal modification condition of EPS particles was discussed with compressive and flexural strength as the reference index, then the best formula of the thermal insulation material was determined with compressive strength and workability as the main reference index. The results show that： when the liquid volume ratio of latex powder emulsion（solid content 40%）/triethanolamine composite modifier is 1：1, volume fraction of the composite modifier is 3%（relative to EPS particles）, and metakaolin coated on the surface of EPS particles is 4 times the mass of the particles, the modified EPS particles show good affinity with the geopolymer cementitious material. Moreover, when the mass fractions（relative to metakaolin） of 3 kinds of admixture（cellulose ether, wood fiber and latex powder） are 0.5%, 0.6% and 3% respectively, volume fraction of EPS particle is 80%, and water cement ratio is 0.66, the performance indexes of the thermal insulation material can basically accord with the requirements of national standard ＂JG 158-2004＂. The dry apparent density, compressive strength, water absorption, softening coefficient and thermal conductivity of the thermal insulation material are 314 kg/m^3, 0.24 MPa, 694 g/m^2, 0.875 and 0.065 W/（m K） respectively, and flame retardancy achieves B1 level.