The recovery of compression set (RS) of wood after dry heating or steam treatment mainly depends on the temperature and time of treatment. For quantitative elucidation, a graph of intermediate RS was built with temper...The recovery of compression set (RS) of wood after dry heating or steam treatment mainly depends on the temperature and time of treatment. For quantitative elucidation, a graph of intermediate RS was built with temperature (T) and time (t) as coordinates. In this graph (abbreviated as T-t planum), a series of curves of RS were created. This leads to a conclusion that same RS can be obtained by numerous different pathways. Further research on pathway equivalency based on T-t planum indicates that a low RS of 10% can be achieved definitely by different combinations of time and temperature. However, the fixation mechanism varies at different temperatures. On the equivalent pathways of higher recovery, the influence of temperature must be taken into consideration. The actual routes must be somewhat modified to achieve an expected result. This makes it possible for us to work out a best fixation pathway among all the possibilities, to eliminate the impact of heat on the mechanical properties of wood.展开更多
in order to increase its hardness and gravity as well as dimension stability, the technology of hotcompressing on P8ulownla wood was studied. The main factors of affecting the spring back of the compressedPaulownis sa...in order to increase its hardness and gravity as well as dimension stability, the technology of hotcompressing on P8ulownla wood was studied. The main factors of affecting the spring back of the compressedPaulownis samples were discussed. It was discovered that every factor in the experiment had obvious effects onwood hardness and dimension stability of compressed wood. When the MC (Moisture Content) of experimentalspecimens was 13.89%, it was useful to spray water on the surface of samples before hot pressing. The best reSult was the recovery of compression set could decrease from 90.69O/O of untreated wood to 45.51 % of soakingspecimens into PF (Phenol Formaldehyde) water solution. The hot pressing time was 8 min at 190℃.展开更多
基金the National Natural Science Foundation of China (Grant No. 30070606) and by Association of International Education of Japan
文摘The recovery of compression set (RS) of wood after dry heating or steam treatment mainly depends on the temperature and time of treatment. For quantitative elucidation, a graph of intermediate RS was built with temperature (T) and time (t) as coordinates. In this graph (abbreviated as T-t planum), a series of curves of RS were created. This leads to a conclusion that same RS can be obtained by numerous different pathways. Further research on pathway equivalency based on T-t planum indicates that a low RS of 10% can be achieved definitely by different combinations of time and temperature. However, the fixation mechanism varies at different temperatures. On the equivalent pathways of higher recovery, the influence of temperature must be taken into consideration. The actual routes must be somewhat modified to achieve an expected result. This makes it possible for us to work out a best fixation pathway among all the possibilities, to eliminate the impact of heat on the mechanical properties of wood.
文摘in order to increase its hardness and gravity as well as dimension stability, the technology of hotcompressing on P8ulownla wood was studied. The main factors of affecting the spring back of the compressedPaulownis samples were discussed. It was discovered that every factor in the experiment had obvious effects onwood hardness and dimension stability of compressed wood. When the MC (Moisture Content) of experimentalspecimens was 13.89%, it was useful to spray water on the surface of samples before hot pressing. The best reSult was the recovery of compression set could decrease from 90.69O/O of untreated wood to 45.51 % of soakingspecimens into PF (Phenol Formaldehyde) water solution. The hot pressing time was 8 min at 190℃.
