A series of poly(butylene sebacate) (PBSe) aliphatic polyesters were successfully synthesized by the melt polycondensation of sebacic acid (Se) and 1,4-butanediol (BDO), two monomers manufactured on an industrial scale from biomass. The number average molecular weight (M_n) in the range from 6116 to 10,779 g/mol and the glass transition temperature (T_g) of the PBSe polyesters were tuned by adjusting the feed ratio between the two monomers. Polylactic acid (PLA)/PBSe blends with PBSe concentrations between 2.5 to 20 wt% were obtained by melt compounding. For the first time, PBSe’s effect on the flexibility and toughness of PLA was studied. As shown by the torque and melt flow index (MFI) values, the addition of PBSe endowed PLA with both enhanced melt processability and flexibility. The tensile tests and thermogravimetric analysis showed that PLA/PBSe blends containing 20 wt% PBSe obtained using a BDO molar excess of 50% reached an increase in elongation at break from 2.9 to 108%, with a negligible decrease in Young’s modulus from 2186 MPa to 1843 MPa, and a slight decrease in thermal performances. These results demonstrated the plasticizing efficiency of the synthesized bio-derived polyesters in overcoming PLA’s brittleness. Moreover, the tunable properties of the resulting PBSe can be of great industrial interest in the context of circular bioeconomy.

This work proposes a new method for obtaining poly(3-hydroxybutyrate) (PHB)/microfibrillated cellulose (MC) composites with more balanced properties intended for the substitution of petroleum-based polymers in packaging and engineering applications. To achieve this, the MC surface was adjusted by a new chemical route to enhance its compatibility with the PHB matrix: (i) creating active sites on the surface of MC with γ-methacryloxypropyltrimethoxysilane (SIMA) or vinyltriethoxysilane (SIV), followed by (ii) the graft polymerization of methacrylic acid (MA). The high efficiency of the SIMA-MA treatment and the lower efficiency in the case of SIV-MA were proven by the changes observed in the Fourier transform infrared FTIR spectra of celluloses. All modified celluloses and the PHB composites containing them showed good thermal stability close to the processing temperature of PHB. SIMA-modified celluloses acted as nucleating agents in PHB, increasing its crystallinity and favoring the formation of smaller spherulites. A uniform dispersion of SIMA-modified celluloses in PHB as a result of the good compatibility between the two phases was observed by scanning electron microscopy and many agglomerations of fibers in the composite with unmodified MC. The dual role of SIMA-MA treatment, as both compatibilizer and plasticizer, was pointed out by mechanical and rheological measurements. This new method to modify MC and obtain PHB/MC composites with more balanced stiffness–toughness properties could be a solution to the high brittleness and poor processability of PHB-based materials.

Polyhydroxybutyrate (PHB) is a biodegradable and biocompatible thermoplastic polymer with good properties.

It is estimated that fossil fuel resources will dwindle by the end of 2050 if the current utilization rate persists

With the continuous depletion of fossil oils and resulting environmental concerns, there is an urgent need to develop polymeric materials from renewable resources [1,2]. Epoxy resins are thermoset polymers that are recognized for their tunable properties (adhesiveness, tensile and electrical strength, stiffness, heat and chemical resistance) and for their various industrial and domestic applications. Still, the main drawback of epoxy resin is its brittleness. Thus, the addition of functional vegetable oils, such as epoxidized linseed oil (ELO), can improve the toughness of epoxy resin, while increasing the bio-based content of the final materials [1]. The goal of this work is to study the influence of composition, cross-linking conditions, and addition of reinforcing agents on the properties of a bio-based epoxy resin, obtained from epoxidized linseed oil (ELO), and a commercial hardener. Nanocellulose from common sources (microcrystalline cellulose MC) and agro-industrial residues (plum seeds shells-SC) were used as fillers in the epoxy-systems. Epoxidized linseed oil (ELO, TRAQUISA, Barcelona, Spain), Epilox—Hardener H 10–30 (G) (NANOCHEM, București, Romania), microcrystalline cellulose (MC) (20 μm, Aldrich, St. Louis, MO, USA) and plum seed cellulose (SC) (laboratory obtained via acidic hydrolysis) were used as raw materials. A 2/1 weight ratio of ELO/G was used to obtain the cross-linked materials. Two types of cellulosic modifiers, MC and SC, were used to reinforce the epoxy systems. The resulted epoxy composite systems were characterized by means of FT-IR, TGA, DMA and water contact angle analysis. TGA analysis showed that the onset and maximum degradation temperatures were increased upon employing an extra cross-linking step at 140 °C or by addition of the cellulosic fillers. Moreover, an increase in the storage modulus of the final epoxy systems was attained as a result of the addition of cellulosic filler, as seen in the DMA results. The addition of a low-weight percentage (0.5%) of cellulose modifiers (MC and SC) enhanced the thermal stability of the epoxy system and had a reinforcing effect by increasing the storage modulus of the final materials.