Biosourced All-Acrylic ABA Block Copolymers with Lactic Acid-Based Soft Phase

Lactic acid is one of the key biobased chemical building blocks, given its readily availability from sugars through fermentation and facile conversion into a range of important chemical intermediates and polymers. Herein, well-defined rubbery polymers derived from butyl lactate solvent were successfully prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization of the corresponding monomeric acrylic derivative. Good control over molecular weight and molecular weight distribution was achieved in bulk using either monofunctional or bifunctional trithiocarbonate-type chain transfer agents. Subsequently, poly(butyl lactate acrylate), with a relative low Tg (−20 °C), good thermal stability (5% wt. loss at 340 °C) and low toxicity was evaluated as a sustainable middle block in all-acrylic ABA copolymers using isosorbide and vanillin-derived glassy polyacrylates as representative end blocks. Thermal, morphological and mechanical properties of copolymers containing hard segment contents of <20 wt% were evaluated to demonstrate the suitability of rubbery poly(alkyl lactate) building blocks for developing functional sustainable materials. Noteworthy, 180° peel adhesion measurements showed that the synthesized biosourced all-acrylic ABA copolymers possess competitive performance when compared with commercial pressure-sensitive tapes.

Modifikasi Resiprene-35 Dengan Asam Metakrilat Melalui Teknik Pencangkokan Dalam Sistem Pelarut

Modifikasi R-35 dilakukan dengan menggunakan monomer olefin turunan akrilat, yakni asam metakrilat. Tujuan modifikasi R-35 menggunakan asam metakrilat adalah untuk memperoleh material adhesion promoter yang sesuai untuk karet alam siklis yang kedepannya diharapkan dapat dimanfaatkan sebagai bahan cat untuk permukaan poliolefin. Proses modifikasi R-35 dengan monomer asam metakrilat dilakukan dalam sistem pelarut pada temperatur 110-140 °C dan desain eksperimental dirancang dengan menggunakan software Qualitek V.4.0. Analisis material R-35 termodifikasi dilakukan dengan menggunakan FTIR dan 1 H-NMR. Analisis FTIR menunjukkan puncak khas daripada ikatan O-H, C-C, C=O, C=C, dan C-O yang mewakili keberadaan daripada R- 35, asam metakrilat dan divinilbenzena. Analisis lebih lanjut %G dengan software Qualitek V.4.0. menunjukkan bahwa %G tertinggi dapat dicapai dengan mengkondisikan reaksi pada T = 140 °C, %MAA = 20%, %DVB = 20, dan t = 180 menit, dengan estimasi %G yang diperoleh adalah 26.08%. Modification of Resiprene-35 (R-35) was carried out using the monomer of olefin acrylic derivative, namely methacrylic acid. The purpose of the modification of the R-35 using methacrylic acid was to obtain an adhesion promoter material suitable for cyclic natural rubber which in the future is expected to be used as a paint material for polyolefin surfaces. The modification process of R-35 with methacrylic acid monomer was carried out in a solvent system at a temperature of 110-140 °C and the experimental design was designed using Qualitek V.4.0 software. The analysis of modified R-35 material was carried out using FTIR and 1 H-NMR. FTIR analysis showed typical peaks rather than O-H, C-C, C = O, C = C, and C-O bonds which represented the presence of R-35, methacrylic acid, and divinylbenzene. Further analysis %G with Qualitek V.4.0 software showed that the highest %G could be achieved by conditioning the reaction at T = 140 °C % MAA = 20%, % DVB = 20%, and t = 180 minutes, with an estimated %G obtained, was 26.08%.

Aminomethylation of chlorophyll a derivatives using bis(N,N-dimethylamino)methane

Bis(N,N-dimethylamino)methane has been shown to be a convenient reagent for the aminomethylation of chlorophyll a derivatives. Methylpheophorbide a (in enol form) and chlorin e 6 13-amides were aminomethylated with bis(N,N-dimethylamino)methane. Reactivity of methylpheophorbide a exo-ring and chlorin e 6 13-amides vinyl group were shown to be different. Selective methylpheophorbide a exo-ring aminomethylation was realized and isomerization of the exo-ring aminomethylation product with rhodochlorin 15-acrylic derivative formation was studied. The action of bis(N,N-dimethylamino)-methane in the presence of weak acid has been shown to be a simple and effective synthetic procedure to obtain a new chlorin e 6 derivative with two N,N-dimethylaminomethyl substituents in the vinyl group. The aminomethylation products' high yields, the simplicity of the procedure, the use of metal-free chlorines and the possible synthesis of new compounds, were found to be the main advantages of using bis(N,N-dimethylamino)methane as an aminomethylation reagent in chlorophyll a derivatives' chemistry.