Influence of the coupling agent and graphene oxide on the thermal and mechanical behavior of tea dust-polypropylene composites

Studies on Glass Fiber-Reinforced Poly(Ethylene-Grafted-Styrene)-Based Cation Exchange Membrane Composite

To improve interfacial adhesion between glass fiber (GF) and poly(ethylene-grafted-styrene)-based cation exchange membranes (CEM), GF was modified by four coupling agents: [3-(Methacryloxy)propyl] trimethoxy silane (3-MPS), 1,6-bis (trimethoxysilyl) hexane (1,6 bis), Poly(propylene-graft-maleic anhydride) (PP-g-MA) and Triethoxyvinylsilane (TES). The results indicated the addition of modified GF increased tensile strength, tensile modulus, storage modulus and interfacial adhesion of GF/CEM composite but degraded the strains. The composite with 3-MPS modified GF obtained superior mechanical properties and interfacial adhesion, whereas the modified effect of TES was inconspicuous. The addition of unmodified GF even had negative effects on GF/CEM mechanical properties. The field emission scanning electron microscopes (FE-SEM) showed that the GF treated by 3-MPS and PP-g-MA have better compatibility with the CEM matrix than 1,6 bis and TES-treated GF. The Fourier-transform infrared spectroscopy (FT-IR) verified that the strengthening effects from modified GF were attributed to the formation of Si-O-Si and Si-O-C bonds. The additions of modified GF in CEM positively influence water uptake ability but negatively influence ion exchange capacity (IEC). This research provided a way of strengthening GF/CEM composite and pointed out which functional groups included in coupling agents could be useful to GF-reinforced composite.

Sustainable Drug Delivery of Famotidine Using Chitosan-Functionalized Graphene Oxide as Nanocarrier

This work mainly focuses on the graphene oxide (GO)-assisted sustainable drug delivery of famotidine (FMT) drug. Famotidine is loaded onto GO and encapsulated by chitosan (CH). UV-visible spectroscopy, field emission scan electron microscopy, and atomic force microscopy confirm the loading of FMT on GO. An interaction of FMT with GO and CH through amine functionalities is confirmed by Fourier-transform infrared spectroscopy. Differential scanning calorimetric and cyclic voltammetric investigations confirm the compatibility of FMT and its retaining activity within chitosan-functionalized graphene oxide (CHGO) composite. Encapsulation efficiency of FMT is determined for various CHGO-FMT combinations and found to be higher at 1:9 ratio. The in vitro drug release profile is studied using a dissolution test apparatus in 0.1 m phosphate buffer medium (pH = 4.5), which shows sustainable drug release up to 12 h, which is greater than the market product (Complete release within 2 h). Comparative study of drug encapsulated with CH and without GO elucidates that GO is responsible for the sustainable release. The "n" value obtained from slope using Korsmeyer-Peppas model suggests the super case-II transport mechanism.