Nanocomposites derived from cellulose acetate and highly branched alkoxysilane

Abstract

Highly branched alkoxysilane (HB) units were prepared in situ via a Michael-type reaction between pentaerythrithol triacrylate and aminopropyltriethoxysilane. These units were used as an inorganic component for the modification of cellulose acetate (CA) films using the sol-gel process. The thermal and dynamic-mechanical behaviors, the morphology, and the dimensional stability of the modified CA films were analyzed. The siloxanemodified CA films showed thermal stability similar to pure CA, but the residue content at 900 C increased with the addition of HB units. The morphology of these films was characterized by siloxane nanodomains dispersed in the CA matrix, with good interfacial adhesion between the phases. Moreover, the CA/siloxane nanocomposite films showed improved dimensional stability in comparison with CA, i.e., in the presence of HB, the dimensional change was reduced to around 50% of the value observed for pure CA. Finally, a complex dynamic-mechanical behavior was obtained for the nanocomposite films, as a consequence of the heterogeneous morphology.

Multifunctional organic–inorganic hybrids based on cellulose acetate and 3-glycidoxypropyltrimethoxysilane

“…Gonçalves et al [9,10] demonstrated the feasibility to tailor a highly branched alkoxysilane CA-based OIH film by grafting pure CA film with 3-aminopropyltriethoxysilane cross-linked with pentaerythritol triacrylate components. The outcome concerns films insoluble in organic solvents and with a significant reduction in the dimensional changes in water when compared to pure CA films.…”

Synthesis of Biopolymer‐Based Precursors for the Formation of Organic–Inorganic Hybrid Materials

“…[10] The modification of CA with 3-glycidoxypropyltrimethoxysilane could be used to incorporate luminescent Eu 3+ -complex or a highly branched alkoxysilane precursor was employed to determine the change in thermal-and dynamic-mechanical properties of CA after crosslinking. [11] On the contrary, the reaction of the functional group of the alkyl substituent, while the alkoxysilane groups remain intact, offers an interesting opportunity for the controlled preparation of organic-inorganic hybrid materials. This approach is very sensitive towards side reactions, because of the high reactivity of the alkoxysilane moieties.…”

“…Hence, an effective conversion could be realized regarding the DS values using in pyridine/DBTL at 80 °C. Products of high DS and even complete functionalization of the OH groups of CA could be obtained (10)(11)(12)(13)(14)(15). However, it turned out that the samples loose solubility with increasing DS that may result from partial hydrolysis of ethoxysilyl moieties and, hence, crosslinking of the polymer chains (12)(13)(14)(15).…”

“…Using CA, covalent bonding of 3‐aminopropyltrimethoxysilane and subsequent protein immobilization is known . The modification of CA with 3‐glycidoxypropyltrimethoxysilane could be used to incorporate luminescent Eu 3+ ‐complex or a highly branched alkoxysilane precursor was employed to determine the change in thermal‐ and dynamic‐mechanical properties of CA after crosslinking …”