Functionalizing natural polymers with alkoxysilane coupling agents: reacting 3-glycidoxypropyl trimethoxysilane with poly(γ-glutamic acid) and gelatin

Abstract

Hybrid materials, with co-networks of organic and inorganic components, are increasing in popularity due to their tailorable degradation rates and mechanical properties. To increase mechanical stability, particularly in water, covalent bonding must occur between the components. This can be introduced using crosslinking agents such as 3-glycidoxypropyl trimethoxysilane (GPTMS). Attachment of GPTMS to polymers in aqueous conditions is hypothesized to occur by opening of the epoxide ring by nucleophiles on the polymer chain. Despite side reactions that occur between the epoxide ring of GPTMS and water, a range of NMR techniques showed that the carboxylic acid group of poly(g-glutamic acid) reacted with GPTMS. This result was used to identify the amino acids in gelatin that reacted most rapidly with the GPTMS epoxide ring, confirming that covalent bonding occurred in gelatin-silica hybrid materials. Journal Name RSCPublishing ARTICLEThis journal is

In vivo immuno‐reactivity analysis of the porous three‐dimensional chitosan/SiO2 and chitosan/SiO2/hydroxyapatite hybrids

“…In class II hybrids, the inorganic and the organic components are covalently crosslinked at the molecular level, and thus they cannot be distinguished at microscale. Connell et al and Wang et al 6,10 confirmed that the hybrid reaction occurred between the epoxide ring of the 3-glycidoxypropyl trimethoxysilane (GPTMS) by the primary amine group (\\NH 2 ) of the CS, and they used inorganic/organic weight ratios (I/Os) and molar ratios of CS and GPTMS showed great influence on the inorganic/organic coupling, the mechanical properties, the degradation behavior, and the scaffold morphology. [4][5][6] In addition, both inorganic and organic components have a congruent degradation behavior and hybrids have the potential for tailoring the material properties such as mechanical properties, degradation rate, scaffold morphology, and others.…”

“…[4][5][6] In addition, both inorganic and organic components have a congruent degradation behavior and hybrids have the potential for tailoring the material properties such as mechanical properties, degradation rate, scaffold morphology, and others. 1-3 Some properties of HOIM are distinctly different to that of the parent inorganic and organic elements.…”

Fabrication of strontium/calcium containing poly(γ-glutamic acid) – organosiloxane fibrous hybrid materials for osteoporotic bone regeneration

“…26 Moreover, we noticed that the band of C]O stretching vibration at 1736 cm À1 which corresponds to the free carboxylic acid (COOH) greatly decreased and new symmetric stretching band at 1419 cm À1 which are assigned to the characteristic bands of carboxyl anion (COO-) appeared, as shown in Fig. 2a.…”

“…3, two signals could be clearly distinguished with typical shis of À57 and À67 ppm which corresponding to the T 2 and T 3 . 24 And the peak area of T 3 was larger than T 2 (T 1 ) in all samples. The weak (absence) of T 1 and the dominance of T 3 suggested that condensation reactions between the silanols from GPTMS alkoxides proceed, agreeing with the results of FTIR in Fig.…”

“…These results suggested that the condensation reaction in GPTMS preceded in the hybrid materials aer electrospinning and dried. 26 Therefore, GPTMS was successful in providing a cross-linking between g-PGA polymer chains through the chemical reactions between carboxyl group on the side chain of g-PGA and epoxy terminated group of GPTMS. The silica was formed by the condensation reaction in GPTMS.…”