Study On Preparation And Performance Of Polyolefin-based Medical Hot-melt Adhesive

Polyolefins are high output and widely applied polymers, among which polyethylene (PE) and polypropylene (PP) are the most commonly used. Polypropylene is a high performance thermoplastic synthetic resin, while because of its non-polar chain and low surface energy, it can barely be adhered, nor blend with other polar polymers or fillers neither. Conventional adhesive has poor adhesive strength on polyolefin such as PP. Besides, common adhesive normally can not be applied in medical field since the existence of multiple industrial additives. Moreover, medical adhesive must match the requirements of steam sterilization in medical field, while existing polyolefin adhesives can hardly satisfy these requirements. In order to solve those problems, this study provides a new hot-melt adhesive that is appropriate for PP membrane and catheter. This hot-melt adhesive employs PPR as matrix material filled with intercalated montmorillonoid (MMT) to improve the barrier of adhesive layer and its tolerance ability during steam sterilization. The formula, fabrication process and properties of the hot-melt adhesive have been studied, and the specific research work includes:1. The modified MMT was intercalated with polyethylene glycol (PEG) through melt or solution intercalation, and both the melt and the solution intercalated MMT were used as filler to blend with PPR. The results illustrated that the gas-barrier property of PPR is improved by adding the modified MMT and the property enhanced with the increasing amount of MMT when the total amount of MMT is less than 4%.2. The medical polyolefin hot-melt adhesive (MPHMA) was prepared by melt blending modified MMT with PPR, PEG and antioxidant in certain proportion. The peel strength of the MPHMA bonded PP films reached to 60N/25mm. The bonding structure remained well sealing even after 30 minutes steam sterilization at 121℃.3. Based on the YBB00042005-2015 standard issued by the State Food and Drug Administration (SFDA), the biomedical property of MPHMA has been test. The results obtained show that both the physicochemical property and the biological property of the MPHMA can satisfy the standard. The maximum adsorption value of the extract of MPHMA in pure water was less than 0.04 at wavelengths of 200-350nm and less than 0.02 at wavelengths of 241-350nm, which conform to the related regulation in the Chinese Pharmacopoeia.4. According to the testing results of medicine compatibility of the MPHMA by HPLC, the MPHMA did not show any extra eluting peaks either in normal saline or in peritoneal dialysis solution, even soaked at high temperature.The drug adsorbability of MPHMA has been studied by XPS and no obvious drug adsorption was observed.