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Aliphatic polyesters such as polylactide (PLA) currently deserve particular attention in the area of environmentally degradable polymer materials. PLA is produced via polymerization of renewable products, namely lactic acid or lactide. In this work, the synthesis of PLA is done by reactive extrusion via ring opening polymerization of L,L-lactide using a continuous single-stage process which is a fast and an easy method. The resulting PLA is fully characterized by solid state NMR. It is shown that it exhibits properties similar to those of PLA synthesized by the traditional methods. A kinetic model based on a phenomenological approach permits one to describe the polymerization of L,L-lactide. PLA nanocomposites containing multi-wall carbon nanotube (MWNT) are also prepared by reactive extrusion. Reaction to fire of PLA nanocomposite shows a slight improvement of the flame retardancy. The nanodispersion characterized by transmission electronic microscopy (TEM) is acceptable but should be improved to obtain the best flame retardancy.

This review discusses the extrusion process parameters and their impact on the mechanical properties of composites reinforced with lignocellulosic fibers.

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This work reports a facile route to synthesize homochiral and stereocomplexed polylactide by reactive extrusion. The effect of the polymerization catalyst (combination of tin(II)octanoate and triphenylphosphine) before and after its deactivation is discussed. Poly‐L‐lactide (PLLA) exhibits homochiral crystallinity and diblock poly‐L,D‐lactide (PDLLA) exhibits stereocomplex crystallinity. The presence of residual monomer leads to a plasticizing effect, reducing glass transition temperature (Tg). Changes of the tacticity (L,D‐tacticity) of the stereocomplex are due to the transesterification reactions between L and D units. Deactivation of the catalyst reduces transesterification reactions and preserves the polylactide stereocomplex upon heating.

In this study, a gradually increased hydro-mechanical treatments duration were applied to native hemp bast fibres with a traditional pulp and paper beating device (laboratory Valley beater). There is often a trade-off between the treatment applied to the fibres and the effect on their integrity. The multimodal analysis provided an understanding of the beating impact on the fibres at multiple scales and the experimental design made it possible to distinguish the effects of hydro-and hydromechanical treatment. Porosity analyses showed that beating treatment doubled the macroporosity and possibly reduced nanoporosity between the cellulose microfibrils. The beating irregularly extracted the amorphous components known to be preferentially located in the middle lamellae and the primary cell walls rather than in the secondary walls, the overall increasing the crystallinity of cellulose from 49.3 % to 59.1 %, but a non-significant change in the indentation moduli of the cell wall was observed. In addition, beating treatments with two distinct mechanical severities showed a disorganization of the cellulose conformation, which significant dropped the indention moduli by 11.2 GPa and 8.4 GPa for 10 and 20 minutes of Valley beater hydromechanical treatment, respectively, compared to hydro-treated hemp fibres (16.6 GPa). Pearson's correlation coefficients between physicochemical features and the final indentation moduli were calculated. Strong positive correlations were highlighted between the cellulose crystallinity and rhamnose, galactose and mannose as non-cellulosic polysaccharide components of the cell wall.

Thanks to its remarkable properties such as sustainability, compostability, biocompatibility, and transparency, poly-Llactic acid (PLA) would be a suitable replacement for oil-based polymers should it not suffer from low flexibility and poor toughness, restricting its use to rigid plastic by excluding elastomeric applications. Indeed, there are few fully biobased and biodegradable transparent elastomers−PLA-based or not−currently available. In the last decades, many strategies have been investigated to soften PLA and enhance its toughness and elongation at break by using plasticizers, oligomers, or polymers. This work shows how a ferulic acid-derived biobased additive (BDF) blends with a common rigid and brittle commercial grade of polylactic acid to provide a transparent non-covalently cross-linked elastomeric material with shape memory behavior exhibiting an elongation at break of 434% (vs 6% for pristine PLA). Through a structure−activity relationship analysis conducted with BDF analogues and a modeling study, we propose a mechanism based on π−π stacking to account for the elastomeric properties. Blending ferulic acid derivatives with polylactic acid generates a new family of fully sustainable transparent elastomeric materials with functional properties such as shape memory.

The homopolymerization in basic conditions of the recently reported bis( -lactone), 2H-HBO-HBO, is herein described for the first time. The solvent-free polymerization of this pentafunctional levoglucosenone (LGO) derivative affords fully renewable poly(vinyl-ether lactone) copolymers with a highly hyperbranched structure. This investigation stems from the polycondensation trials between 2H-HBO-HBO and di(methyl carbonate) isosorbide (DCI) that fails to give the anticipated polycarbonates. Such unexpected behavior is ascribed to the higher reactivity of the 2H-HBO-HBO hydroxy groups toward its , -conjugated endocyclic C═C, rather than the DCI methylcarbonate moieties. The different mechanistic scenarios involved in 2H-HBO-HBO homopolymerization are addressed and a possible structure of poly(2H-HBO-HBO) is suggested. Furthermore, the readily accessible (S)--hydroxymethyl-, -butenolide (HBO) is also polymerized for the first time at a relatively large scale, without any prior modification, resulting in a new hyperbranched polymer with an environmental factor (E factor) ≈0. These new HBO-based polymers have a great potential for industrial-scale production due to their interesting properties and easy preparation via a low-cost, green, and efficient process.