The Research About Natural Decay Resistance Of The Cork And Products

Cork displays the quality of strong corrosion resistance in the application of its products,the essay provides measurement standards which can be as the main reference to wood natural corrosion resistance, testing the quality of corrosion resistance of cork bark, analyzing the variations of the cork chemical contents, microscopic structure, penetrability, density, the corrosion resistance of cork floor and changes of color and rebound resilience when compressed during the decayed process. The research results are as the follows:(1) There is little variation in the weight of cork only within 1 %, of which, the weight loss of white rot accounts for the most ( about 1.294%), next to it is brown rot (accounting for 1.045%), mildew rot accounts for the least(0.977%), Compared with the natural wood's corrosion resistance, we learn that cork has the extraordinary strong natural corrosion resistance and ranks top among the woods.(2) The three hyphae experience three periods, and they are lag phase, fast growing season and recession phase, of whom the lag phase of cotiolus versicolor and Gloeophyllum trabeum lasts longer, about 2 days, while Chrysonilia sitophila lasts for 1 day. During the period of growth, the hyphae of cotiolus versicolor and Gloeophyllum trabeum is shorter with the ply of 1 mm. Chrysonilia sitophila grows very fast with longer hyphae and thicker ply which may be as thick as 8mm and the ply will decrease to 3mm.(3) After the decay process, the overall change is little within 0.5%. The main content of cork is suberin, which the fungus can't degrade, which becomes the main reason of its corrosion resistance. Cork also contains more lignin and ensemble cellulose, which becomes the main degraded substance for the fungus, whose effects is little in cork. According to the poor permeability of cork, we set test conditions as 1.7MPa pressure and 114℃, there is no change between the good cork and decayed one on their permeability. The density of the cork displays no change after the decay process.(4) The observation through the SEM shows that no hyphae are found inside the cork. Single cork cell got through the method of cork segregation remains the same as the original with complete shape.(5) Trough the segregation of hyphae, we concluded that only the mildew (Chrysonilia sitophila) is able to enter cork inside, while white rot and brown rot can just grow on the surface of the cork without invading into the cork. (6) 12 mesh cork floor shows a little variation after decaying, whose range is within 3.5%.The weight loss of 4 mesh cork floor is so little that you will find it to be same as the original cork. And the weight loss after twelve weeks is about 1.2%. Mildew has little effect on the weight of the 12 and 4 mesh cork. Although mildew grows on the surface of the cork, it doesn't destroy cork color. Cork floor and the contrast cork floor△E*,△L*,△a*,△b* observe the consistent variation rules. It is still in accordance with cork changes after decay with regard to its rebound resilience when compressed, that is to say the changes of cork floor has no relationship with mildew. The reason relating to rebound resilience changes of the cork needs further research. It shows in the experiment of segregation of hyphae that the growth of hyphae in cork is the same as in cork floor, because of which, the quality of corrosion resistance is not destroyed after adding adhesive to the cork floor.