Fabrication And Evaluation Of Amphiphilic SIS-g-NPEO Hot-Melt Pressure Sensitive Adhesives

Styrene-isoprene-styrene (SIS) based HMPSAs have very hydrophobic, which greatly restricts their application in TDDS.To solve this problem, chemical grafting method is used to improve the hydrophilicity of SIS, as the basis for preparation of amphiphilic HMPSA.ESIS was prepared through epoxidation of SIS thermoplastic elastomer. Then a hydrophilic group (nonylphenol polynoxyethylene ether, NPEO) was introduced by alkali grafting ring-opening reaction of ESIS, which lead to a novel amphipathy SIS-g-NPEO thermoplastic elastomer. And SIS-g-NPEO was later prepared as amphiphilic hot melt pressure sensitive adhesive. Fourier transform infrared spectroscopy (FT-IR) and hydrogen nuclear magnetic resonance (1HNMR) were used to characterize the epoxy degrees of ESIS and grafting efficiency of ESIS. Geniposide and oleanolic acid were used as model drugs to investigate drug release behavior in varied SIS-g-NPEO. When the mass ratio of NPEO (grafting chains) to SIS was 3.5:1.0-4.0:1.0, the SIS-g-NPEO could achieve continual release of both hydrophilic and lipophilic drugs.In order to further explore the drug release mechanism in SIS-g-NPEO, we examined the hygroscopicity and thermodynamic behavior of the varied SIS-g-NPEO. The results showed that varied SIS-g-NPEO could maintain thermoplasticity and independent crystalline domain of NPEO; when the mass ratio of NPEO to SIS was above 3.5:1.0, SIS-g-NPEO swelled greatly and amphiphilic structure was formed. Micromorphology of SIS-g-NPEO polymers were analyzed by scanning electron microscopy (SEM). The solubility parameters indicated that NPEO was easier to penetrate into PS, which lead to the interface of PS and PI became blurred and PS became continuous phase.Based on the SIS17-g-NPEO(NPEO:SIS=3.5:1.0,w/w), following the gradually addition of an appropriate amount of polyethylene glycol (PEG), mineral oil and tackifier resin, the amphiphilic PSAs were prepared.In this study, the effects of various components on the adhesion property of HMPSA was examined by orthogonal experiments; the preparation technology and the composition of HMPSA were optimized and verified. In order to confirm the relationship between the components and the release profile of geniposide by gradually adding component to prepare HMPSAs patches.