Bio-based poly(ethylene terephthalate) copolyesters made from cyclic monomers derived from tartaric acid

Tricyclic Diester and 2,5-Furandicarboxylic Acid for the Synthesis of Biobased Hydrolysis Copolyesters with High Glass Transition Temperatures

The reluctance of a polyester with high glass transition temperature (Tg) and mechanical properties to hydrolyze is a well-known fact, for instance, the high hydrolysis resistance of aromatic polyesters based on terephthalic acid and 2,5-furandicarboxylic acid (FDCA). The synthesis of polyesters that have a high Tg (>100 °C) and a fast hydrolytic degradation quality at the same time is a valuable topic. Herein, a renewable rigid diester, N,N'-trans-1,4-cyclohexane-bis(pyrrolidone-4-methyl carboxylate) (CBPC), was obtained via Michael addition. CBPC was copolymerized with FDCA and ethylene glycol to prepare a series of copolyesters PECxEFy with a high Mn over 30 kDa. PECxEFy showed a Tg range of 75.2-109.2 °C which outdistanced the most biobased polyesters. The thermal stability of all PECxEFy remained unchanged with the introduction of CBPC. Moreover, PECxEFy presented superior mechanical performances which were matching or exceeding those of commercial polyethylene terephthalate (PET) and polylactic acid (PLA). PECxEFy was stable in air but was able to undergo noticeable hydrolytic degradation, proving their enhanced degradability. And the regulation between CBPC and FDCA composition can be leveraged to adjust the degradation and environmental durability of PECxEFy, up to practical applications. Computational studies systematically revealed the relationship between CBPC with a tricyclic structure and the improved Tg and hydrolyzation properties. The outstanding thermal and mechanical performances and hydrolysis of these copolyesters appear to be promising candidates for renewable alternatives to industrial petrochemical polyesters.

Agri-Food Wastes for Bioplastics: European Prospective on Possible Applications in Their Second Life for a Circular Economy

Agri-food wastes (such as brewer's spent grain, olive pomace, residual pulp from fruit juice production, etc.) are produced annually in very high quantities posing a serious problem, both environmentally and economically. These wastes can be used as secondary starting materials to produce value-added goods within the principles of the circular economy. In this context, this review focuses on the use of agri-food wastes either to produce building blocks for bioplastics manufacturing or biofillers to be mixed with other bioplastics. The pros and cons of the literature analysis have been highlighted, together with the main aspects related to the production of bioplastics, their use and recycling. The high number of European Union (EU)-funded projects for the valorisation of agri-food waste with the best European practices for this industrial sector confirm a growing interest in safeguarding our planet from environmental pollution. However, problems such as the correct labelling and separation of bioplastics from fossil ones remain open and to be optimised, with the possibility of reuse before final composting and selective recovery of biomass.

Bio-Degradable Polyesters with Rigid Cyclic Diester from Camphor and Tartaric Acid

Despite their excellent, useful, and stable properties, thermoplastics are constantly subject to environmental risks because of their low degradability under thermal, chemical, and mechanical stresses. To overcome the aforementioned issues, we hereby introduce an eco-friendly camphor (Ct) cyclic diester. The Ct diester is designed as a monomer, including a ketal group from the Ct, and shows high thermal stability via a rigid spiro-ring and a bridged bicyclic structure. A series of polyester was synthesized using the Ct diester, including various types of diols and dimethyl terephthalate. PETxCty copolyesters showed appropriate thermal stability up to 414 °C and a high glass transition temperature. This thermal behavior led to amorphous regions as the Ct diester content increased. Regarding the proportion of the Ct diester in the polyester, it was sensitive to hydrolysis and contributed to the degradation of the polyester in acid buffer conditions.

Melt polycondensation of 2,5-tetrahydrofurandimethanol with various dicarboxylic acids towards a variety of biobased polyesters

The effects of THFDM's structure on its reactivity, polymer molecular chain energy and properties were systematically studied.

In situ synthesis of poly(ether ester) via direct polycondensation of terephthalic acid and 1,3-propanediol with sulfonic acids as catalysts

Sulfonic acid-comprising catalysts were explored to in situ fabricate ether segments in the process of esterification of terephthalic acid and 1,3-propanediol, and developing a new pathway of poly(ether ester)s synthesis without the addition of oligoether as starting materials.

Thermoplastic polyacetals: chemistry from the past for a sustainable future?

This review serves as a guide to the synthesis and applications of thermoplastic polyacetals, highlighting in particular sustainability and degradability aspects.

Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) random copolymers: effect of copolymer composition and microstructure on the thermal properties and crystallization behavior

The glass transition temperature of the statistically random PETG copolymers increased linearly with the increasing CT content. An increase in the average sequence length resulted in a higher melting temperature.