Synthesis of semitelechelic POSS-polymethacrylate hybrids by thiol-mediated controlled radical polymerization with unusual thermal behaviors

A Rapid One-Pot Synthesis of Novel High-Purity Methacrylic Phosphonic Acid (PA)-Based Polyhedral Oligomeric Silsesquioxane (POSS) Frameworks via Thiol-Ene Click Reaction

Herein, we demonstrate a facile methodology to synthesis a novel methacrylic phosphonic acid (PA)-functionalized polyhedral oligomeric silsesquioxanes (POSSs) via thiol-ene click reaction using octamercapto thiol-POSS and ethylene glycol methacrylate phosphate (EGMP) monomer. The presence of phosphonic acid moieties and POSS-cage structure in POSS-S-PA was confirmed by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (¹H, 29Si and 31P-NMR) analyses. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrum of POSS-S-PA acquired in a dithranol matrix, which has specifically designed for intractable polymeric materials. The observed characterization results signposted that novel organo-inorganic hybrid POSS-S-PA would be an efficacious material for fuel cells as a proton exchange membrane and high-temperature applications due to its thermal stability of 380 °C.

Thiomers: A Blessing to Evaluating Era of Pharmaceuticals

Thiomers are the polymers modified for the mucoadhesive properties and other additive properties by incorporating thiol moieties in the backbone of the unmodified polymeric chain by substitution reactions or simple oxidation reactions. Drugs that are less soluble and permeable can be complexed with thiomers for their increased absorption through the mucosal membranes by increase in contact time and prolonged stay in body due to mucoadhesion. Immobilization of thiol group therefore increases the mucoadhesive properties of the modified polymer by 2–140-folds. The prepared thiomers are characterized and made stable by different techniques. Thiomers also give the controlled delivery of the active pharmaceutical ingredients in the body. Different polymers that are modified by thiolation are chitosan, polyacrylic acid, sodium alginate, sodium carboxy methyl cellulose, guar gum, and so forth. Thiomeric formulations are a challenge to deliver drugs with low therapeutic compatibility. Micro- and nanopreparations containing thiomers can be prepared by different techniques such as covalent crosslinking, in situ gelation, radical emulsion polymerization, and emulsification. Nowadays thiomers have wide range of applications as a promising pharmaceutical excipient in the evaluating era of pharmaceutical technology.

Star-shaped POSS diblock copolymers and their self-assembled films

This first example of 16-arm, star-shaped diblock copolymers s-POSS-PMMA_277.3-b-P(MA-POSS)_{5.8,16.4,25.4} can be used as solvent-dependent coatings.

Synthesis and thermal stability of hybrid polymers using UV photopolymerization based on polyhedral oligomeric silsesquioxanes

A series of hybrid polymers based on methacrylphenyl polyhedral oligomeric silsesquioxanes (MA-POSS) and methylmethacrylate (MMA) were rapidly synthesized via UV photopolymerization through a (2,4,6-trimethylbenzoyl)diphenylphosphine oxide-initiated reaction. The structure and morphology of hybrid polymers were characterized via Fourier transform infrared spectroscopy, proton nuclear magnetic spectroscopy, gel permeation chromatography, X-ray diffraction, transmission electron microscopy and scanning electron microscopy, which confirmed that the MA-POSS cage could be successfully incorporated into the polymethylmethacrylate (PMMA) chain. The obtained hybrid polymers had no obvious aggregation of MA-POSS. It can be concluded that MA-POSS were well-dispersed in the hybrid polymers. The thermal properties of PMMA–POSS hybrid polymers were investigated through differential scanning calorimetry and thermogravimetric analysis. Results show that the incorporation of POSS cage results in the enhancement of the glass transition temperature and the decomposition temperature of hybrid polymers as compared with PMMA polymers without MA-POSS.