Poly(3-hydroxyalkanoate) sulfonate: From nanoparticles toward water soluble polyesters

Preparation and Characterization of Calcium Carbonate Masterbatch-Alkali Soluble Polyester/Polyester Porous Fiber via Melt Spinning

Porous fibers have gained significant attention for their lightweight and high porosity properties in applications such as insulation and filtration. However, the challenge remains in the development of cost-effective, high-performance, and industrially viable porous fibers. In this paper, porous fibers were fabricated through the melt spinning of an alkali soluble polyester (COPET)- CaCO3 masterbatch and PET slice. Controlled alkali and acid post-treatment techniques were employed to create porous structures within the fibers. The effects on the morphology, mechanical, thermodynamic, crystallinity, pore size, and thermal stability were investigated. The results indicate that the uniform dispersion of CaCO3 particles within the fiber matrix acts as nucleating agents during the granulation process, improving the thermal resistance and strength of the porous fiber. In addition, the porous fiber prepared by COPET/CaCO3 to PET with an 85/15 ratio and post-treated on 4% NaOH and 3% HCl exhibits a "spongy body" with uniformly small pores, favorable strength (2.71 cN/dtex), and elongation at break (47%).

Hydrogel Based on Polyhydroxyalkanoate Sulfonate: Control of the Swelling Rate by the Ionic Group Content

Hydrogels based on poly(3-hydroxyalkanoate) (PHA) sulfonate and poly(ethylene glycol) diacrylate, PEGDA, are prepared. First, PHA sulfonate is synthesized from unsaturated PHA by a thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. The hydrophilicity of PHAs is considerably increased by adding sulfonate functions, and three amphiphilic PHAs are synthesized, containing 10, 22, or 29% sulfonate functions. Then, hydrogels are formed in the presence of PEGDA having different molar masses, that is, 575 or 2000 g mol^-1. The hydrogels show fibrillar and porous structures observed in cryo-MEB with pore sizes that vary according to the content of sulfonated groups (10 to 29 mol %) ranging from 50 to more than 150 nm. Furthermore, depending on the proportions of the two polymers, a variable rigidity is observed from 2 to 40 Pa. In fact, the evaluation of the dynamic mechanical properties of the hydrogel determined by DMA reveals that the less rigid hydrogels hinder the adhesion of Pseudomonas aeruginosa PaO1 bacteria. Finally, these hydrogels swelling up to 5000% are noncytotoxic, allowing the adhesion and amplification of immortalized C2C12 cells, and they are therefore seen as promising materials both for repelling PaO1 bacteria and for amplifying myogenic cells.

Study of Mechanical Properties of PHBHV/Miscanthus Green Composites Using Combined Experimental and Micromechanical Approaches

In recent years the interest in the realization of green wood plastic composites (GWPC) materials has increased due to the necessity of reducing the proliferation of synthetic plastics. In this work, we study a specific class of GWPCs from its synthesis to the characterization of its mechanical properties. These properties are related to the underlying microstructure using both experimental and modeling approaches. Different contents of Miscanthus giganteus fibers, at 5, 10, 20, 30 weight percent's, were thus combined to a microbial matrix, namely poly (3-hydroxybutyrate)-co-poly(3-hydroxyvalerate) (PHBHV). The samples were manufactured by extrusion and injection molding processing. The obtained samples were then characterized by cyclic-tensile tests, pycnometer testing, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and microscopy. The possible effect of the fabrication process on the fibers size is also checked. In parallel, the measured properties of the biocomposite were also estimated using a Mori-Tanaka approach to derive the effective behavior of the composite. As expected, the addition of reinforcement to the polymer matrix results in composites with higher Young moduli on the one hand, and lower failure strains and tensile strengths on the other hand (tensile modulus was increased by 100% and tensile strength decreased by 23% when reinforced with 30 wt % of Miscanthus fibers).

Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3 + or tannic acid TA-N(CH3)3 +. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3 +, the mechanical properties increased in the presence of TA-N(CH3)3 + with an elastic modulus G' around 4200 Pa. The PHOSO3 -/TA-N(CH3)3 + gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.

Synthesis of highly branched water-soluble polyester and its surface sizing agent strengthening mechanism

Solvent-free and highly branched water-soluble polyester (WPET) is prepared through self-emulsification methodology, using dimethyl terephthalate (DMT), sodium dimethyl isophthalate-5-sulfonate (SIPM), trimethylolpropane (TMP), and ethylene glycol (EG) by the transesterification and polycondensation. The WPET were first utilized as surface-sizing agents for cellulose fiber paper. The structure, average molecular weights, and physical properties of the water-soluble polyester were characterized by FTIR, 1H NMR, gel permeation chromatography (GPC), dynamic light scattering (DLS), X-ray diffraction (XRD), and dynamic rheometer. The effects of polymer structure and properties, as well as the surface sizing of the paper, were investigated. WPET displayed better surface sizing properties when it was prepared under the following conditions: –COO/–OH molar ratio of 1:2, the SIPM content of 17.98%, and TMP content of 11.10%. The relationships between the WPET structure and sized paper were clearly illustrated. The mechanical properties and water resistance of sized paper did not only depend on multi-branched hydroxyl groups of the WPET chains but also relied on the interactions among polymers and fibers, as well as the high toughness of surface sizing agent. The sizing paper possesses excellent mechanical properties as well as water resistance.

Fabrication, characterization, and application of polyester/wood flour composites

The mechanical properties, thermal properties, antibacterial activity, and fabrication of three-dimensional (3D) printing strips of composite materials containing polyhydroxyalkanoate (PHA) and wood flour (WF) were evaluated. Maleic anhydride (MA)-grafted PHA (PHA-g-MA) and WF were used to enhance the desired characteristics of these composites. The PHA-g-MA/WF composites had better mechanical properties than the PHA/WF composites did. This effect was attributed to a greater compatibility between the grafted polyester and WF. Additionally, the PHA-g-MA/WF composites provided higher quality 3D printing strips and were more easily processed because of ester formation. The water resistance of the PHA-g-MA/WF composite was greater than that of PHA/WF. Moreover, WF enhanced the antibacterial activity of the composites. Composites of PHA-g-MA or PHA containing WF had better antibacterial activity.

Chemically Intractable No More: In Vivo Incorporation of "Click"-Ready Fatty Acids into Poly-[(R)-3-hydroxyalkanoates] in Escherichia coli

Poly-[(R)-3-hydroxyalkanoate] biopolymers, or PHAs, are biocompatible and biodegradable polyesters that can be produced by diverse microbial strains. PHA polymers have found widespread uses in applications ranging from sustainable replacements of nonbiodegradable bulk-commodity plastics to biomaterials. However, further expansion into other markets and industries has generally been limited by the inability to chemically modify these polymers. Recently, our lab engineered E. coli LSBJ, a microbial strain able to produce PHA copolymers with controlled unit compositions from simple and accessible fatty acid feedstocks. We envisioned meaningfully broadening the application spectrum of these materials via production of chemically tractable PHA biopolymers containing "click"-ready chemical functionalities. With a myriad of applications in mind, in this study we demonstrate the synthesis and biopolymerization of a panel of ω-azido fatty acids and take the first exploratory steps toward demonstrating their conjugation via a strain-promoted azide-alkyne cycloaddition (SPAAC) reaction. The convenience of accessing these materials will open the door to new applications for functionalized PHA polymers.