Study About The Characteristic Of Poplar Surface By The Treatment Of Low Temperature Plasma

This paper is based on the study of the surface properties of poplar treated by plasma, five different gas plasmas are used to treat poplar for changing the surface wettablity. And poplar graft acrylic acid(AAc) on the surface after plasma treatment. It can improve the surface properties of poplar and raise its stability and timeliness. this topic is designed to be a comprehensive system of the study of the wood surface properties modified.Firstly poplars treated by gas plasmas such as helium, air, oxygen, argon and nitrogen are researched. The order of five kinds of gas plasmas by improving the surface wettablity: argon≈helium> nitrogen> air> oxygen. The best plasma processing time is 3 minutes, and the contact angle of the poplar treated by plasma is 92% more than the poplar untreated. The poplar treated by plasma place for some time, the surface wettablity will reduce gradually, although that will not recover like before, that is because of the sculpture of the poplar surface treated by plasma. The research shows that the plasma processing has the problem of timeliness.Secondly, the surface appearance and relatively free radicals concentration of poplar are studied. After treated by plasma, the smooth surface of poplar becomes a coarsening, and we can see some crisscross appeared on the surface. Except that, relatively free radicals concentration of the poplar treated by plasma is bigger than the poplar untreated. The order of relatively free radicals concentration created by five different gas plasma:argon≈helium> nitrogen> air> oxygen.Thirdly poplar graft acrylic acid(AAc) on the surface after plasma treatment is studied. The best technology parameters of stem grafting polymerization is:temperature is 50℃, AAc concentration is 6mol/L, polymerization time is 8 hours. After placing the poplar for some time, the contact angle is 17°all the time. That implies there are some hydrophily functional groups on the surface of poplar, which solve the problem of timeliness.Fourthly, the surface appearance and chemicals of poplar are studied. After grafting acrylic acid(AAc) on the surface of poplar, the rough surface is disappeared, like being covered by something. From the infrared spectrum form of samples, we could find new hydroxyl characteristic peak which belongs to carboxylic acid and RCOO characteristic peak, we also can find double bond characteristic peak. So after stem grafting polymerization, the chemicals of poplar have great changes.