Study On Preparation And Properties Of Polyethylene Film Coated Anti-fogging And Grafted Silane

Polyethylene film coated anti-fogging was widely used in greenhouses due to it's good properties of anti-fogging, transmittance as well as long duration of anti-dropping. It was difficult to coat anti-fogging agent onto polyethylene film,to solve the situation, the method of corona treatment was usually adopted to increase the surface polarity in industry. But corona treatment caused a lot of problems such as power consumption, film aging and degradation, pollution the environment, reducing mechanical properties and so increasing the polarity of polyethylene film to improve the coating performance was of great significance.Based on this, high polarity coated anti-fogging silane grafting polyethylene was prepared through chemical modification. It lay the foundation for the preparation of long anti-dropping duration coated anti-fogging polyethylene film.Silane grafting polyethylene which used in film was prepared with DCP,silane A-171, inhibitor and other additives for grafting system. This paper mainly studied the effect of type and content of inhibitor on the properties of the silane grafting polyethylene. At the same time, in order to simplify the process, PV was used as a initiator to prepare the silane crosslinking polyethylene, for the aim to study the effect of PV dosage and reaction temperature on the properties of the silane crosslinking polyethylene.Results showed that these inhibitor include the homemade inhibitor, sodium dodecyl sulfate and N, N- dimethyl formamide did worked on inhibit side reaction, among them, homemade inhibitor worked best. When the homemade inhibitor dosage was 0.3 phr, maximum relative grafting rate reached 1.61,maximum surface tension was 36×10-3 N/m, minimum crystallinity and themechanical properties was well. The relative grafting rate and gel content of silane crosslinking polyethylene increased with the increasing of PV dosage and reaction temperature. While the PV dosage reached 0.25 phr and the reaction temperature reached 170 ?, maxium relative grafting rate reached 1.25 and gel content reached 11.3 %.Anti-fogging agent was prepared with silica sol, alkyl fatty amine, sodium dodecyl sulfate, homemade alumina sol as raw materials, and it was prepared by certain proportion, to study the effect of composition and dilution ratio on the anti-fogging agent performance.The results showed that minimum surface tension reached 34×10-3 N/m at the homemade aluminium sol dosage of 17.65 vol%. At this best dosage, the antifogging agent could be coated onto the film most easily. The surface tension of anti-fogging agent was increased with the increase of dilution ratio, spurt after diluted 10 times. Gel time reached 73 h when diluted 10 times. While increasing the dilution ratio multiple times, the gel time tend to be stable.Therefore the best prepare condition of anti-fogging agent was homemade aluminium sol when the dosage reached 17.65 vol% and the diluted multiples reached 10 times.Properties of polyethylene film coated anti-fogging and silane grafted were studied, and the transmittance and haze was compared with ordinary polyethylene anti-fogging film, corona treatment anti-fogging film.Results showed that the transmittance of normal anti-fogging polyethylene film, corona treatment and silane grafting polyethylene film was 90 %, 92 %, and94 % respectively. The anti-dropping duration at 60 ? of normal anti-fogging polyethylene film, the corona treatment anti-fogging polyethylene film reached,and polyethylene film coated anti-fogging and grafted silane reached 8 d, 20 d and 19 d respectively. The anti-dropping duration of corona treatment and silane grafting cross-linking modification was basically equal, at the same time much higher than that of normal anti-fogging polyethylene film.