Study of Interior Wall Coating Based on Metakaolinand Modified Starch
In order to reduce the emission of volatile organic compounds (VOCs) and save the non-renewable resource, a novel interior wall coating with high bond strength based on metakaolin and modified starch was developed. The process on researches includes three steps. Firstly, cassava starch was reformed including etherification, oxidation, conjugate crosslinking and drying to gain natural polymer glue powder which can be used as forming agent, and a dispensation in producing environment friendly paint for interior wall coating was preliminarily obtained. The dispensation consists of forming agent, calcium carbonate, French chalk, chitosan and mildew preventive. Secondly, the process on metakaolin was studied. Metakaolin shows hydration Characteristics and can make interior wall coating have bond strength and resistance to water. At last, the dispensations and processes in obtaining starch glue, metakaolin and paint powder were decided respectively, and the data in gauging bonding force, resistance to water and the performance of interior wall coating were gained. The research on forming agent was as following: the mixture of cassava starch and NaOH was stirred, and pulverized to be sieved by100 mesh. After reacted stirringly with chloroacetic acid for 1.5h at room temperature, the mixture was oxidized by oxidant for 2h and crosslinked by crosslinking agent for 1h respectively to obtain forming agent. The mass fraction of NaOH, chloroacetic acid, oxidant and crosslinking agent to cassava starch were 6%, 5%, 6% and 0.8%, respectively. The Kaolin selected must contain high percents of Al2O3 and SiO2 , and was calcined at 700°C for 5h to have metakaolin as additive for interior wall coating to improve bond strength and resistance to water. The composition of interior wall coating optimized by orthogonal test is about: 4% of starch glue, 6% of metakaolin, 80% of calcium carbonate, 9.7% of French chalk, 0.1% of chitosan and 0.2% of mildew preventive. The interior wall coating is environmental benign material in building industry.
Zhong Cao, Xueqiang Cao, Lixian Sun, Yinghe He
R. J. Zhou et al., "Study of Interior Wall Coating Based on Metakaolinand Modified Starch", Advanced Materials Research, Vols. 239-242, pp. 1030-1035, 2011