Synthesis and Characterization of ABA-Type Triblock Copolymers Using Novel Bifunctional PS, PMMA, and PCL Macroinitiators Bearing p-xylene-bis(2-mercaptoethyloxy) Core

Abstract

Syntheses of novel bifunctional poly(methyl methacrylate) (PMMA)-, poly(styrene) (PS)-, and (poly ε-caprolactone) (PCL)-based atom transfer radical polymerization (ATRP) macroinitiators derived from p-xylene-bis(1-hydroxy-3-thia-propanoloxy) core were carried out to obtain ABA-type block copolymers. Firstly, a novel bifunctional ATRP initiator, 1,4-phenylenebis(methylene-thioethane-2,1-diyl)bis(2-bromo-2-methylpropanoat) (PXTBR), synthesized the reaction of p-xylene-bis(1-hydroxy-3-thia-propane) (PXTOH) with α-bromoisobutryl bromide. The PMMA and PS macroinitiators were prepared by ATRP of methyl methacrylate (MMA) and styrene (S) as monomers using (PXTBR) as the initiator and copper(I) bromide/N,N,N′,N″,N″-pentamethyldiethylenetriamine (CuBr/PMDETA) as a catalyst system. Secondly, di(α-bromoester) end-functionalized PCL–based ATRP macronitiator (PXTPCLBr) was prepared by esterification of hydroxyl end groups of PCL-diol (PXTPCLOH) synthesized by Sn(Oct)2–catalyzed ring opening polymerization (ROP) of ε-CL in bulk using (PXTOH) as initiator. Finally, ABA-type block copolymers, PXT(PS-b-PMMA-b-PS), PXT(PMMA-b-PS-b-PMMA), PXT(PS-b-PCL-b-PS), and PXT(PMMA-b-PCL-b-PMMA), were synthesized by ATRP of MMA and S as monomers using PMMA-, PS-, and PCL-based macroinitiators in the presence of CuBr/PMDETA as the catalyst system in toluene or N,N-dimethylformamide (DMF) at different temperatures. In addition, the extraction abilities of PCL and PS were investigated under liquid–liquid phase conditions using heavy metal picrates (Ag+, Cd2+, Cu2+, Hg2+, Pb2+, and Zn2+) as substrates and measuring with UV-Vis the amounts of picrate in the 1,2–dichloroethane phase before and after treatment with the polymers. The extraction affinity of PXTPCL and PXTPS for Hg2+ was found to be highest in the liquid–liquid phase extraction experiments. Characterizations of the molecular structures for synthesized novel initiators, macroinitiators, and the block copolymers were made by spectroscopic (FT–IR, ESI–MS, 1H NMR, 13C NMR), DSC, TGA, chromatographic (GPC), and morphologic SEM.

Synthesis and Properties of Modified Biodegradable Polymers Based on Caprolactone

“…It was shown in prior work [ 18 ] that CL allows the moderate development of two micromycetes, Fusidium viride and Penicillium brevicompactum , capable of biosynthesizing enzymes that accelerate biotic reactions and trigger the biodegradation of the copolymer. This destruction can be a potentially toxic action for the environment, and it is absolutely necessary to monitor the impact on the plant’s metabolism, given the conversion of the copolymer into simple substances that can modify the metabolic activity and implicitly the structure of the plant [ 19 ]. Following the decomposition of the copolymer, the nitrogen dynamics undergo evolutionary changes, confirming the process’s development with the release of organic nitrogen.…”

“…In addition, the biological tests carried out (germination index, average seedling height, green and dry biomass) on Lypercosium esculentum , San Marzano variety tomato plants that were in direct interaction with the copolymer showed their normal growth and development, which suggests a negligible toxic effect and implicitly a compatibility of the copolymer with the environment [ 18 ]. Given the essential role of this pigment in photosynthesis and, indirectly, in the metabolism and physiological state of the plants, it is very important to quantify the total chlorophyll content of the plant leaves that came into contact with the copolymers [ 19 ]. By mixing CL with other polymers (such as polydimethylsiloxane), it is possible to synthesize copolymers or composites with modified physical, chemical, and mechanical properties [ 20 ].…”

“…The literature studies of the synthesis, characterization, and properties of PDMS-CL copolymers are limited. However, the PDMS-CL copolymer-based microspheres have unique properties and can be used to obtain biomedical devices such as scaffolds in tissue engineering and matrix resins for time-release drugs [ 9 , 19 ]. Polydimethylsiloxane (PDMS) has a very low glass transition temperature, which makes it a soft segment to adjust the mechanical properties of CL-based shape memory polymers (SMPs) [ 21 ].…”

Achieving Less Than 100 ppb Total Metal Ion Concentration in ESCAP Resins Synthesized by Atom Transfer Radical Polymerization

“…[25,[28][29][30] Gao et al [31] synthesized poly(4-acetoxystyrene) via ATRP, achieving a PDI of 1.11-1.18; Chen et al [32][33][34] prepared poly(4-acetoxystyrene-b-styrene-b-isobutene) via ATRP, resulting in a PDI range of 1.22-1.68. Lai et al [35] and Misir et al [36] separately synthesized PS-b-PMMa block copolymers for use as photoresist resin by ATRP, with PDI of 1.28-1.75 and 1.09-1.42, respectively. Boni et al [37] synthesized PS-b-PMMA block copolymer by ATRP and NMP, with a PDI of 1.10.…”