Poly[(R)‐3‐hydroxybutyrate)]/poly(styrene) blends compatibilized with the relevant block copolymer

Abstract

A novel triblock copolymer PS–PHB–PS based on the microbial polyester Poly[(R)‐3‐hydroxybutyrate)] (PHB) and poly(styrene) (PS) was prepared to be used as compatibilizer for the corresponding PHB/PS blends. It was prepared in a three‐step procedure consisting of (i) transesterification reaction between ethylene glycol and a high‐molecular‐weight PHB, (ii) synthesis of bromo‐terminated PHB macroinitiator, and (iii) atom transfer radical polymerization polymerization of styrene initiated by the PHB‐based macroinitiator. Fourier transform infrared, gel permeation chromatography, 1H‐, and 13C‐NMR spectroscopies were used to determine the molecular structure and/or end‐group functionalities at each step of the procedure. Although thermogravimetric analysis showed that the block copolymer underwent a stepwise thermal degradation and had better thermal stability than their respective homopolymers, differential scanning calorimetry displayed that the PHB block in the copolymer could not crystallize, and thus generating a total amorphous structure. Atomic force microscopy images indicated that the block copolymer was phase segregated in a well‐defined morphological structure with nanodomain size of ∼40 nm. Contact angle measurements proved that the wettability properties of the block copolymer were in between those of the PHB and PS homopolymers. Blends analyzed for their morphology and thermal properties showed good miscibility and had well‐defined morphological features. Polymer blends exhibited lower crystallinity and decreased stiffness which was proportional to the amount of compatibilizer content in the blends. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

PMLABe Diol Synthesized by Ring‐Opening Polymerization of Racemic Benzyl β‐Malolactonate Initiated by Rare‐Earth Trisborohydride Complexes: An Experimental and DFT Study

“…Also, owing to their biocompatibility, biodegradability and, non‐toxicity, they are candidates of special interest for biomedical applications 2. Poly(3‐hydroxybutyrate) (PHB), the ubiquitous PHA, has been synthesized as a diol and subsequently used as a macroinitiator in the copolymerization of 1) other cyclic esters upon ring‐opening polymerization (ROP) (e.g., ε‐caprolactone,3 lactide4) or of 2) acrylates (e.g., methyl methacrylate),5 styrene,1d and acrylamides6 by radical polymerization. PHB diols were also enabled to prepare PHB‐based polyurethanes7 further evaluated as thermogelling copolymers8 or promising biomaterial candidates 9…”

Poly(3‐hydroxybutirate‐co‐3‐hydroxyvalerate)–Polystyrene Hybrid Nanoparticles via Miniemulsion Polymerization

“…Hybrid nanoparticles, despite a small border effect, presented a more homogeneous structure in agreement with the high‐grafting yield and FTIR and DSC results. In the case of PHBV–PS blend nanoparticles, some degree of phase separation can be observed, presenting an outer region composed of the more hydrophilic polymer, PBHV (gray arrow) and an inner region composed of polystyrene (white arrow) due to their incompatibility . This was also observed in the case of acrylic–alkyd resin due to the low grafting between the polymers …”

Thermally stable low‐density polyethylene/polyhydroxybutyrate pairs: Synergy between organomodified nanoclay and LDPE‐g‐MAH

“…They studied samples with equal parts PHB and PS with different compatibilizer loadings. 32 However, the trend is not the same for PHB-matrix phase systems as seen in Figure 6. As a matter of fact, the presence of a compatibilizer enhances neither energy of activation nor the onset degradation temperature.…”

“…demonstrated that a triblock copolymer of PS–PHB–PS enhanced the thermal stability of a PHB/PS binary blend. They studied samples with equal parts PHB and PS with different compatibilizer loadings . However, the trend is not the same for PHB‐matrix phase systems as seen in Figure .…”

“…As seen, introduction of a compatibilizer causes an increase in the values of E a , T onset , and T d , especially for 2.5 wt % of compatibilizer when LDPE is the matrix. Abdelwahab et al 32 demonstrated that a triblock copolymer of PS-PHB-PS enhanced the thermal stability of a PHB/PS binary blend. They studied samples with equal parts PHB and PS with different compatibilizer loadings.…”