Study On The Effect Of Properties For High Temperature Hot Water Treatments

This paper used 6 years Phyllostachys pubescens bamboo as the research object,by adopting different temperature(120 ~ 160)and time(60 min,90 min,120 min)of high temperature hot water process,analyzing the change of chemical composition of bamboo,color,mechanical properties and dimensional stability with different process,we so as to explore the high temperature hot water process and the relationship between property of bamboo,and get the best modification technology that was suitable for industrialized production and market,the following main conclusions were obtained:(1)The effect of temperature on the content of main chemical composition and mass loss was significant,not for time,and by the correlation analysis,the mass loss significantly correlated to the holocellulose and a-cellulose.When temperature at 120~140,a-cellulose?acid insoluble lignin content and mass loss increase gradually,holocellulose slightly decreased;During 140~160,with the increase of temperature and the extension of time,the holocellulose and a-cellulose content gradually reduced,acid insoluble lignin content and mass loss were increased.With the increase of processing temperature,hydroxyl and carbonyl absorption peak intensity gradually decline,cellulose,the loss of hydroxyl of amorphous areas was the main cause of bamboo dimension stability improved.(2)With the improvement of high temperature hot water temperature and time,the color of Phyllostachys pubescens bamboo gradually change to the deep coffee color.The color of untreated bamboo was yellow,the color of 120?~140?processing was to be near brown,the color of 150? the bamboo surface was brown,and the color of 160? was dark brown.The effect of temperature and time on the color L*,a*,b* and discoloration E* was significant.The color L*,a*,b* showed a trend of gradual decline with the increase of temperature and time,the color degree of E* increased gradually.By the correlation analysis,the E* and holocellulose?a-cellulose had negative correlation,and acid insoluble lignin content was significantly positively related.(3)The trend of mechanical strength(in addition to the MOE)was consistent with holocellulose content with temperature and time increase.The MOE decreased gradually first and then remain unchanged but then gradually reduced with the increase of temperature,in 120?~130? temperature range,MOE decreased gradually,in 130?~140? temperature range,MOE remain the same,in 140 ~160?temperature range,MOE decreased gradually.The effect of temperature and time had a great influence on the mechanical properties of the bamboo,but the processing time had not significant impact on the MOE.The mechanical properties were significantly related to holocellulose and a-cellulose by the correlation analysis,but was closely related with holocellulose.The optimum process of mechanical properties of high temperature hot water of modified bamboo as follows: extraction temperature 120?,time of 60 min.(4)The effect of temperature and time had a great effect on EMC,the EMC of modification Phyllostachys pubescens bamboo increased with the increase of processing temperature and time.Which the temperature between 120?~140?,EMC was not obviously declined,between 140?~160?,EMC reduced significantly.The effect of temperature and time on the drying shrinkage rate was significant.With the increase of processing temperature and time,the bamboo drying shrinkage rate showed a trend of gradual decline,inflection point appears at 140?.The optimum process of dimensional stability of high temperature hot water extraction of modified bamboo as follows: extraction temperature 160?,time of 120 min.