Polyamidoamines (PAAs) are synthetic, biocompatible and biodegradable polymers obtained by the aza-Michael stepwise polyaddition of prim- or sec-amines with bisacrylamides. PAAs have shown potential application in the biomedical field, such as drug and protein intracellular carriers, transfection promoters, antiviral, antimalarial agents and, in hydrogels form, as scaffold for tissue engineering. However, PAA hydrogels are not suitable as implantable materials due their poor mechanical properties. Different approaches were investigated to overcome this problem, as the preparation of composites with inorganic fillers or PLLA mats. The new approach reported here is based on the development of hydrophobic, semi-crystalline PAAs with sufficient mechanical strength to be used as hydrogel supports. Hydrophobic PAAs were prepared from long chain aliphatic bisacrylamides and different diamines. In particular, the monomers employed were: as for the bisacrylamides, N,N’-hexamethylene-bisacrylamide (HEXAMBA), N,N’-octamethylene-bisacrylamide (OMBA), N,N’-decamethylene bisacrylamide (DMBA) and N,N’-dodecamethylene bisacrylamide (DDMBA), obtained by the Schotten-Baumann reaction involving acryloyl chloride and 1,6-diaminehexane, 1,8-diamineoctane, 1,10-diaminedecane or 1,12-diaminedodecane, respectively; as for the amine monomers, piperazine (PIP), N,N’-dimethyl-1,6-hexanediamine (DMHEXA), N,N’-dimethyl-1,2-ethanediamine (DMEDAsym), N,N-dimethyl-1,2-ethanediamine (DMEDAas), N,N’-dibenzyl-1,2-ethanediamine (DBEDA) and N,N’-diethyl-1,2-ethanediamine (DEEDA). The polymerization reactions were first performed in benzyl alcohol solution, for two days at 60°C. The products were retrieved by precipitation with excess diethyl ether. All PAAs were characterized by FT-IR/ATR and NMR spectroscopies. DSC and TGA calorimetric analyses were performed to investigate the thermal properties of the hydrophobic PAAs. All PAAs exhibited good thermal stability, with decomposition onset temperatures ≥ 200 °C and were semi-crystalline. The amine moieties seem to exert the main influence on the thermal properties of the final product. For instance, being the bisacrylamide moiety the same, the melting points range from 195 °C (DDMBA-PIP) to 50°C (DDMBA-DMEDAas). The bisacrylamide influence exists but is less evident. For instance, being the amine moiety the same, the melting points range from 80 °C (HEXAMBA-DMHEXA), to 100°C (DDMBA-DMHEXA). The mechanical properties were studied on thin films obtained by compression molding. On the whole, all polymers tested were successfully filmed. The best flexible and resistant films were those deriving from the DDMBA-based polymers, such as DDMBA-DMHEXA or DDMBA-DMEDAs. To settle a more sustainable process, a bulk polymerization process was preliminarily studied to prepare DDMBA-DMHEXA and OMBA-DMHEXA. The reaction was carried out under inert atmosphere and in the presence of a radical inhibitor at 140°C or 150°C for DDMBA-DMHEXA or OMBA-DMHEXA, respectively. Preliminary results showed that lower molecular weight, but comparable thermal properties were observed with respect to samples obtained with the solution process. In addition, the yield strength of DDMBA-DMHEXA was higher than that of OMBA-DMHEXA with 10.14 ± 0.58 MPa and 4.72 ± 1.43 MPa, respectively.
Hydrophobic polyamidoamines : a new class of technological materials? / E. Ranucci, M. Marcioni, B. Immirzi, G. Dal Poggetto, J. Alongi, A. Manfredi, P. Ferruti. ((Intervento presentato al convegno Chemicals & Materials for Emerging Technologies (CheMET) tenutosi a Doha nel 2020.
|Titolo:||Hydrophobic polyamidoamines : a new class of technological materials?|
RANUCCI, ELISABETTA (Corresponding)
|Data di pubblicazione:||15-nov-2020|
|Parole Chiave:||hydrophobic polyamidoamines|
|Settore Scientifico Disciplinare:||Settore CHIM/04 - Chimica Industriale|
|Enti collegati al convegno:||Springer|
|URL:||https://www.youtube.com/watch?v=O_3jRq9XZ98, Chemicals & Materials for Emerging Technologies (CheMET) 2020 - Day 2, https://www.youtube.com/embed/W16_IWqzZCw|
|Citazione:||Hydrophobic polyamidoamines : a new class of technological materials? / E. Ranucci, M. Marcioni, B. Immirzi, G. Dal Poggetto, J. Alongi, A. Manfredi, P. Ferruti. ((Intervento presentato al convegno Chemicals & Materials for Emerging Technologies (CheMET) tenutosi a Doha nel 2020.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|