Lauric diacid (LCDA), also known as 1,12-dodecanedioic acid, is used to develop a series of copolyesters along with 1,4-cyclohexanedicarboxylic acid (CHDA) and 1,4-butanediol (BDO). The resulting poly(butylene lauric dicarboxylate-co-butylene 1,4-cyclohexanedicarboxylate) (PBLC) is proved to be a random copolyester with three triad sequences. When the LCDA content increases from 20 to 60 mol%, Tm of the copolyester decreases from 133 to 57 °C. At the same time, the tensile modulus and strength decrease from 94 and 14 MPa to 40 and 5 MPa, respectively. Moreover, the elongation at break also drops from 640 to only 50%. However, further increasing the LCDA content to 80 mol%, the copolyester becomes amorphous with no Tm, and its tensile modulus, strength, and the elongation at break all improve significantly to 68 and 7 MPa, and over 1400%, respectively. More importantly, for the homo-polymer poly(butylene lauric dicarboxylate) (PBL), it has a relatively high Tm of 73 °C compared to that of polycaprolactone (PCL), but lower tensile modulus and strength, and significantly higher ductility, compared to those of PCL, linear low density polyethylene, and polybutylene succinate.

By covalently immobilizing imidazolium ion onto molecular chain, functional polyurethane (PU) is fabricated and thus an effective way is initiated to prepare electrospun membranes with antibacterial activity. In the experiment, PUs containing imidazolium ion side group (Bmim-PUs) are synthesized through a two-step polymerization process. It includes prepolymerization of isophorone diisocyanate (IPDI) with polyester glycol and chain extension polymerization using imidazolium-based ionic diol (Bmim-OH). Then, the obtained Bmim-PUs are electrospun into fibrous membranes with a diameter of ~640 nm. After a careful assessment, antibacterial activities of electrospun membranes against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli are clearly exhibited. The antibacterial efficiency of Bmim-PUs on both bacteria species improves by 60% in comparison with PU without imidazolium ion. This research suggests a simple but effective methodology to design and fabricate ultrafine fibrous membrane with significant antibacterial activity. Moreover, the obtained fibrous membranes have widely potential applications in protective textiles, filtration, and biomedical engineering.

By researching the transition of the crystal form of regenerated cellulose (RC) during hydrolysis, the key factor to achieving highly effective hydrolysis under microwave radiation is adequately recognized as reducing the formation of cellulose I during hydrolysis. With the suitable use of sulfolane, the formation of cellulose I within the process of recrystallization during hydrolysis is inhibited and thus highly promotes the reactivity of RC. Accordingly, the effectiveness of the hydrolysis of regenerated cellulose is successfully induced. The more sulfolane is used, the less cellulose I forms. As a result, a more effective hydrolysis of RC is produced. After increasing the ratio of sulfolane to 80 wt %, the conversion of cellulose is obviously improved with the highest amount over 98%. Under this condition, the yield of total reducing sugars is up to 71.9%. On the basis of controlling the transition of crystal form of regenerated cellulose, our research not only suggests an effective way to hydrolyze RC, but also provides an understanding of the critical principle of reducing the formation of cellulose I within the process of recrystallization during hydrolysis to initiate the hydrolysis of cellulose with high effectiveness.Keywords: Biomass; Cellulose I; Hydrolysis; Microwave radiation; Sulfolane

Non-planar ring contained polyester is synthesized as an effective toughening agent to modify polylactide (PLA). By systematically researching the relation between molecular structure and properties, the two key factors to pursue high toughness of PLA with non-planar ring contained polyester are carefully distinguished. For one thing, the polyester must own the ability to be well compatible with PLA. For the other, the polyester should have a rigid molecular chain but “non-rigid” aggregation structure. By suitably controlling the molecular design, poly(butylene adipate-co-1,4-cyclohexanedicarboxylate) (PBAC) is obtained. After using PBAC to toughen PLA, the elongation extremely increases to 196.1 ± 3.6% and the notched impact strength is also effectively improved with several times. Finally, our research establishes an important methodology to toughen PLA and thus fabricates tough PLA based blends.

Phenylboronic acid and folate grafted chitosan hydrochloride (FHCSPBA) was synthesized and confirmed by FTIR and 1H NMR. Glucose and pH dually responsive micelles were obtained through self-assembly of the amphiphilic polymers. The prepared FHCSPBA micelles displayed good biocompatibility and sustained drug release of the model drug doxorubicin hydrochloride (DOX). The cumulative drug release from the polymeric micelles showed obvious pH and glucose dependence and was accelerated by slightly decreasing the medium pH or increasing the glucose concentration. In vitro antitumor efficiency was evaluated by incubating the DOX loaded micelles with 4T1 breast cancer cells, and the results showed that folate-targeted micelles had higher antitumor activity than the non-targeted ones. Cellular uptake demonstrated by confocal microscopy indicated that free DOX was internalized in the nuclei of 4T1 cells, while the DOX loaded micelles were internalized in the cytoplasm. The cellular uptake of the micelles was enhanced by folate, with stronger fluorescence intensity in the cytoplasm, due to active FR-mediated endocytosis. These folate-conjugated glucose and pH dually responsive micelles may be a potential antitumor drug delivery system for cancer chemotherapy.

A unique non-planar ring structure 1,4-cyclohexanedicarboxylic acid (CHDA) is introduced to synthesize a poly(butylene adipate-co-butylene 1,4-cyclohexanedicarboxylate) (PBAC) copolyester. The impact of the stereochemistry of CHDA on the structure and properties of PBAC, especially the role of cis-CHDA in tuning the thermal, tensile and elastic properties of PBAC is explored in depth. Instead of considering PBAC as a diblock random copolymer consisting of poly(butylene adipate) (PBA) and poly(butylene 1,4-cyclohexanedicarboxylate) (PBC), our results reveal that PBAC can be considered as a random copolymer consisting of actually three blocks, namely PBA, a PBC unit with only trans-CHDA (trans-PBC), and PBC unit with only cis-CHDA (cis-PBC). The role of cis-CHDA is found to be rigid which initiates a high modulus and strength, and soft which results in a decreased melting temperature and increased elongation at break and elasticity.

A soft segment free thermoplastic polyester elastomer is fabricated by controlling the stereochemical structure of molecular chains with the utilization of the cis 1,4-cyclohexylene ring moiety (cis-CHRM) in poly(butylene 1,4-cyclohexanedicarboxylate) (PBC). PBC with 71% cis-CHRM exhibits good elasticity with shape recovery rates of 64% at 200% strain and 92% at break, tensile modulus, strength and elongation at break at 111 and 18 MPa and 1230%, respectively.

Polyurethanes (TPUs) containing carbon–carbon double bonds are synthesized for use as novel materials with the ability to form functionalizable ultrafine fibers via electrospinning. By adjusting the molecular structure, a series of TPU products with different amounts of carbon–carbon double bonds are obtained. After investigating the reactivity of the TPU with 1H,1H,2H,2H-perfluorooctanethiol, all of the TPU samples exhibit effective functionalizability. The more carbon–carbon double bonds contained in the molecular structure, the stronger the functionalizability. Besides, these TPUs can easily form uniform ultrafine fibers via electrospinning. Upon comparison, the functionalizability of the electrospun fibers is similar to that observed in the bulk TPU materials. This work suggests a feasible methodology to produce a functionalized ultrafine fibrous carrier. Accordingly, TPU containing carbon–carbon double bonds is expected to be exploited as a fibrous carrier of solid catalysts in the future.

•Monohydric alcohol is the optimal activation agent of corn cellulose in dissolving.•Activated agent requires small size, low viscosity, and single functionality.•After activation, cellulose can be electrospun to fibers with good morphology.Water and four small molecular alcohols are respectively used to activate corn cellulose (CN cellulose) with the aim to improve the dissolvability in DMAc/LiCl. Among all these activated agents, monohydric alcohols are found to produce the optimal effect of activation in the whole process including of activating, dissolving, and electrospinning of CN cellulose. Meanwhile, well distributed fibers with the diameter of 500 nm–2 μm are fabricated in electrospinning. Understanding the activation effect of monohydric alcohols with water and polyhydric alcohols, the most effective activated agent is ascertained with the characteristics of small molecular size, low viscosity, and single functionality. This work is definitely initiated to understand the critical principle of CN cellulose in dissolving. Accordingly, a feasible methodology is also established to prepare ultrafine cellulose fibers with good morphology in electrospinning.

Epoxidized citric acid (ECA) is synthesized as a highly reactive bio-based compatibilizer to improve the flexural property of polylactide (PLA)/microcrystalline cellulose (MCC) blends. Confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analysis, ECA includes three oxirane groups in its chemical structure with the rather high epoxy value at 0.76. After adding 1–5 wt % ECA in PLA/MCC blends, the interfacial adhesion between PLA and MCC is significantly improved. Accordingly, flexural strength, flexural modulus as well as impact strength of PLA/MCC/ECA blends are all improved and thus the increase of the flexural properties. This work suggests an effective way to create biobased compatibilizer with high reactivity and hereby displays a feasible way to fabricated fully bio-based PLA/MCC blends with high performance.

A novel zinc-stabilized UV-Fenton reaction is created to decompose cellulose under mild, organic solvent-free conditions. Cellulose is successfully decomposed to form a valuable C2 chemical, namely glycolic acid. The zinc ion enhances the yield of glycolic acid via complexation. The whole process is simple, rapid and controllable. This method shows a great commercial potential due to its simplicity and mild reaction conditions.

Thermal and tensile properties of thermoplastic elastomers (e.g. poly(butylene terephthalate)-b-poly(tetramethylene glycol) (PBT–PTMG)) are usually tuned by changing the composition of hard and soft segment parts. Simply increasing the amount of soft segment results in a lower melting temperature and better elastic properties, but the thermal stability and tensile properties are inevitably sacrificed. In this work, by incorporation of an aliphatic ring structure (i.e. 1,4-cyclohexanedicarboxylic acid) (CHDA) to partially replace the aromatic ring (i.e. terephthalic acid) in PBT-PTMG, the properties of the material can be tuned in such a way that the melting temperature decreases, while the thermal stability, tensile and elastic properties are not compromised. Moreover, manipulation of the stereo-chemistry of the CHDA unit discloses the “elastic” nature of the non-planar ring structure. Samples with a greater amount of cis-CHDA tend to have better tensile and elastic properties compared with their trans-CHDA counterparts.

Poly(butylene terephthalate)-poly(tetramethylene glycol) (PBT-PTMG) copolymer is prepared with terephthalic acid (PTA) rather than its dimethyl ester (DMT) as starting material by a two-step melt polycondensation. This process includes the synthesis of PBT prepolymer from PTA with 1,4-butanediol (BDO) in the first step, followed by the synthesis of PBT-PTMG copolymer from PBT prepolymer with PTMG in the second step. The molecular weight, composition as well as thermal and mechanical properties of the products from the two-step melt polycondensation are compared with the properties of the PBT-PTMG from the traditional one-step melt polycondensation. When the PTMG content is low, there is only slight difference in molecular weight, composition, thermal and mechanical properties among PBT-PTMG copolymers obtained from these two methods. However, when the PTMG content is high, only the two-step strategy is able to give high molecular weight products, and the products have comparable thermal and mechanical properties with those from traditional one-step strategy using DMT as starting material.

A biobased monofunctional compatibilizer (called Epicard) is first synthesized by the reaction of cardanol with epichlorohydrin as confirmed by Fourier transform infrared and 1H NMR. Subsequently, biosourced polymers, polylactide (PLA) and starch, are melt-blended by a twin-screw extruder with Epicard. Confirmed by the measurements of contact angle and 1H nuclear magnetic resonance of the extracted starches from PLA/starch/Epicard blends, the Epicard only possesses a monoepoxy group to mainly react with starch and then increased the hydrophobicity of the starches during the melt-blending process. As a result, an obvious improvement to the interfacial adhesion between starch and PLA is observed by the scanning electron microscopy. Furthermore, the tensile properties of PLA/starch blends are effectively improved with the addition of Epicard. This study suggests a simple but effective material technique by utilizing a novel plant oil modifier to increase interfacial adhesion in fabricating fully biobased PLA/starch blends with superior tensile properties.

A soft segment free thermoplastic polyester elastomer is fabricated by controlling the stereochemical structure of molecular chains with the utilization of the cis 1,4-cyclohexylene ring moiety (cis-CHRM) in poly(butylene 1,4-cyclohexanedicarboxylate) (PBC). PBC with 71% cis-CHRM exhibits good elasticity with shape recovery rates of 64% at 200% strain and 92% at break, tensile modulus, strength and elongation at break at 111 and 18 MPa and 1230%, respectively.