Study On Polyolefin Blockcopolymers Of Hot Melt Pressure Sensitive Adhesive

This article presentation main characteristics and several preparation methods for the ethylene-1-octene copolymer (POE) as the representative of the polyolefin block polymer, Polyolefin block copolymer is discussed in the application of hot melt pressure sensitive adhesive and its development prospect was put forward.In the experimental study we take the molten synthetic method to prepare POE-g-MAH. Through the analysis of Fourier transform infrared spectra (FT-IR) and differential scanning calorimetry spectra (DSC), proved that the maleic anhydride (MAH) was well-off grafted onto the POE. The effects factor in grafting monomer content, initiator content, reaction temperature and reaction time adjustment on the grafting rate of polymer were discussed, and detect the contrast and analysis of the corresponding gel rate. The experimental results showed:The grafting ratio will be increased until reached the maximum and then decrease with increasing maleic anhydride inputs, the gel rate will be increased to the highest value, and then decreased with the increasing maleic anhydride content; Increasing the initiator content, the grafting rate increases to a certain extent and then decreased slowly, the gel rate will continue to elevate until completely gel; increasing the reaction temperature, the grafting rate will gradually increase and then steady decline, the impact on the gel is not very obvious, the scope of product gel rate can keep stable; Longer reaction time, at the beginning the graft rate increase quickly, then the growth rate slowed down, also the gel rate maintain the stable range.In this paper by means of several inspection methods such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), positron annihilation (PAT) and dynamic rheological measurement, to study on graft copolymer of various performance along with the change of grafting rate of growth. Research shows that:As the success of the maleic anhydride grafted, the rise in the numbers of branch chain, makes the structure of polyolefin performance is not so stable, resulting in POE-g-MAH melting temperature, the crystallization temperature, the crystallinity and thermal decomposition temperature and so on will appear because of grafting rate improve slightly decreased; The positron annihilation lifetime τ3values increased with the temperature increases gradually, the glass transition temperature (Tg) of polymer can be determined, but is not fixed, but also depends on the detection time, the longer the time, the lower the glass transition temperature, the more to the theoretical value, found that at a certain temperature range, the free volume parameters of polymer will deviate from the linear relationship; In the low frequency range, with the POE-g-MAH graft rate increases, the energy storage modulus G’, shear modulus G"and complex viscosity η*will also rise. through the G’G"in the process of change can get recognized reaction with gel formation in POE-g-MAH, in the process of machining, the grafted polymer η*showed more prominent shear thinned behavior, namely with the increase of shear stress, surface viscosity smaller.The preparation of polyolefin block copolymer used in hot melt pressure sensitive adhesive test, obtained the good test results. It has excellent thermal/oxidation stability, better workability, viscosity stability, belongs to the green environmental protection product. Preparation technology is simple control, convenient and easy to implement mass production, is a prospect of the new type of adhesive materials.