Synthesis And Properties Of Atactic Polypropylene Grafted Acrylate

Polypropylene materials with low surface energy, polar small, high crystallinity andother characteristics, therefore they are difficult to be directly bonded or coated. Inthe fields of adhesives and coatings, polypropylene applications usually requirecorona, plasma and other secondary pre-processing, or use modified chlorinatedpolypropylene as an adhesive, which is often synthesised in benzene solution. Thispaper presented a new feasible method to modify atactic polypropylene (APP). Thatis, withdicumylperoxide (DCP)asinitiator reagent, atactic polypropylene wasgrafted through radical polymerization in butyl acetate solution. The method canreplace traditional the non-environmental adhesive, which is made chlorinatedpolypropylene in benzene solution, to bond polyo lefin, reducing the pollution of theenvironment and the human body.In this paper, through―grafting from‖, the monomers, such as acrylamide,acrylic acid, butyl acrylate, methyl methacrylate, isobornyl methacrylate, laurylacrylate were successfully grafted onto atactic polypropylene to obtain the graftcopolymer. Modified epoxy-acrylate was used as crosslinking agent to improve thecohesive strength and solvent resistanceof the graft copolymer, which processedexcellent adhesion propertiesfor PP. According to FT-IR and DSC analys is results,the graft mechanism of APP was explored under the system.This paper explored the factors that influence the peel strength. Firstly, the peelstrength increased with the content of APP, acryla mide and isobornyl acrylate andthen decreased. Secondly, within a certain range, modified epoxy-acrylate promotedthe peel strength. Ultimately, because the reaction was performed by droppingprocess, the amount of DCP had no regular influence on the peel strength. However,as the molecular weight increased, the peel strength presented rising on the wholewithin a certain range, while excessive molecular had negative effect on peelstrength decrease. In addition, it was indicated that the desirable molecular weightdistribution was benificial to the peeling strength.Based on the analysis results of surface performance, XPS and DSC, combinedwith the relevant literture, the adhesion mechanism between APP grafted copolymerand PP was proposed. The contact angle demonstrated that the surface tension ofadhesive was less than BOPP film’s, meeting the thermodynamic conditions that theadhesive could infiltrate the substrate. According to the change of surfacemorphology, it was showed that the molecular motion of the substrate and theadhesive exacerbated at a higher temperature, which satisfied the kinetic conditions of infiltration. Under the above conditions, the adhesion between APP graftedcopolymer and PP was stabilized by diffusion-infiltration primally, supplemented bycrystallization.Combined with the appropriate silica and water-white rosin resins, APP graftedcopolymer could be used to prepare the adhesive layer of hot stamping foil, whichpresented excellent splitting performance and fastness for a variety of substrates,such as BOPP film and most ink-paper. In addition, VOCs test results showed thatthe volatile organic compound in the adhesive layer could fully meet therequirement of the standard.