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Background: Stable upper limb fractures, such as radius, ulna, or distal humerus fractures, are common pediatric orthopedic traumas that are traditionally managed with cast immobilization. The commonly used synthetic fiberglass cast is light and water resistant but may promote skin itchiness during casting, which is a common complaint of patients. In addition, these diisocyanate-based casts have been proven to be toxic and may cause asthma. Herein, we introduce a novel biobased polyester cast to compare its clinical outcomes and patient satisfaction with conventional synthetic fiberglass casts. Methods: From Feb 2022 to Nov 2022, we undertook a single-center prospective randomized trial involving 100 children with cast-immobilized stable upper limb fractures. These patients were randomized into either biobased polyester or synthetic fiberglass groups. All patients were regularly followed up till the cast removal which occurred approximately 3–4 weeks after immobilizing. Objective clinical findings and subjective patient questionnaire were all collected and analyzed. Results: According to the radiographs taken on the day of cast removal, there was no loss of reduction in both groups. The incidence of skin problems was 3.4 times higher in the synthetic fiberglass group than in the biobased polyester group. For the subjective questionnaire, the biobased polyester cast was preferred in every sub-item. Conclusions: Our study strongly suggested that the novel biobased polyester cast provides matching stability to conventional fiberglass casts and improves patient satisfaction in an eco-friendlier and safer way. Trial registration: ClinicalTrials.gov Protocol Registration and Results System (https://www.clinicaltrials.gov/; ID: NCT06102603; Date: 26/10/2023). [ABSTRACT FROM AUTHOR]

Hot-melt adhesives are solid adhesives that are converted to a melting state for application to substrates and on cooling efficiently sets up the bond. Due to low or no volatile organic compound emissions, hot-melt adhesives are extensively used in various applications. Poly(trimethylene terephthalate- co -adipate) copolymers containing dimethyl terephthalate, adipic acid, and 1,3-propanediol along with varying amounts of castor oil were synthesized by one-step melt polymerization as hot-melt adhesives. The structure, composition, and thermal properties of these samples were analyzed, and all samples showed excellent thermal stability with Td-5% values above 300°C. Differential scanning calorimetry measurements showed tunable melting temperatures of the copolymers in the range of 80–180°C, which increased with the content of dimethyl terephthalate and decreased with increasing amounts of castor oil. The incorporation of castor oil as soft segments enhanced the flexibility of the molecular chain, indicating an increment in the elongation rate while decreasing the stress at the break and glass transition temperatures. Rheological examinations showed significant increments in the viscosity at lower angular frequencies with the introduction of castor oil; this was attributed to the entanglement caused by the multifunctional groups of castor oil with dangling chains in the segments. As the angular frequency increased, the viscosities of the samples decreased almost linearly, revealing good applicability in the melting process of the copolymers, which presented controllable melting viscosities under different process conditions. The T-peel test was used to investigate the adhesion properties of the copolymers, and the copolymer with 50/50 molar ratio of dimethyl terephthalate/adipic acid with 3 mol% castor oil PT(T50A50)-C3 exhibited excellent binding capacity between the copolymer and poly(ethylene terephthalate) fabric with a peel strength of 2624.5 N m−1. Moreover, PT(T50A50)-C3 shows low moisture absorption, good hydrolysis resistance, and relatively low hardness, which indicates its high potential for application in hot-melt adhesives on polyester fabrics with high strength, good tactile quality, and long service life. [ABSTRACT FROM AUTHOR]

A series of multiblock copolymers poly(ethylene terephthalate)‐co‐poly(ethylene glycol)‐poly(propylene glycol)‐poly(ethylene glycol) (PET‐X%‐E‐P‐E) were synthesized from dimethyl terephthalate (DMT), ethylene glycol (EG) and poly(ethylene glycol)‐poly(propylene glycol)‐poly(ethylene glycol) (E‐P‐E) with a two‐step procedure via melt polymerization. The structure, composition, crystallization behavior, and thermal stability of the synthesized copolymers were determined by 1H‐NMR, FT‐IR, XRD, DSC, and TGA measurements. All samples exhibited good thermal stability at a Td‐5% above 300°C. DSC results revealed an increment trend of crystallization ability of copolymers in lower E‐P‐E content and then decreased when E‐P‐E concentration gradually raised to 40 wt%. Furthermore, the mechanical properties of copolymers were investigated systematically; the incorporation with E‐P‐E segments significantly enhanced the toughness and water absorption ability. Impact strength increased from 670.46 to 4448.75 J/m2, and water absorption values raised from 0.7% to 3.4% of the content of E‐P‐E increased. The stress–strain curve exhibited that tensile strength reduced from 40.38 to 17.88 MPa, the elongation at break increased from 4.6 to 27.9%. These new tough PET materials have an important application in toughness polyester fiber by the melt‐spinning techniques. [ABSTRACT FROM AUTHOR]

Bio-based unsaturated poly(butylene adipate-co-butylene itaconate) (PBABI) aliphatic copolyesters were synthesized with pentaerythritol (PE) as a modifier, observing the melting point, crystallization, and glass transition temperatures were decreased from 59.5 to 19.5 °C and 28.2 to −9.1 °C as an increase of itaconate concentration, and Tg ranged from −54.6 to −48.1 °C. PBABI copolyesters tend to the amorphous state by the existence of the BI unit above 40 mol%. The yield strength, elongation, and Young's modulus at different BA/BI ratios were valued in a range of 13.2–13.8 MPa, 575.2–838.5%, and 65.1–83.8 MPa, respectively. Shear-thinning behavior was obtained in all BA/BI ratios of PBABI copolyesters around an angular frequency range of 20–30 rad s−1. Furthermore, the thermal and mechanical properties of PBABI copolyesters can be well regulated via controlling the itaconic acid contents and adding the modifier. PBABI copolyesters can be coated on a 3D air mesh polyester fabric to reinforce the mechanical property for replacing traditional plaster applications. [ABSTRACT FROM AUTHOR]

Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). All samples had excellent thermal stability at a Td−5% around 370 °C. Crystallization temperature (Tc) and enthalpy of crystallization (ΔHc) were detected by differential scanning calorimetry (DSC), revealing a decrement from 182.3 to 135.1 °C and 47.0 to 22.1 J g−1, respectively, with the increase in PTMEG concentration from 0 to 40 wt%. Moreover, nonisothermal crystallization was carried out to explore the crystallization behavior of copolymers; the crystallization rate of PBT reduced gradually when PTMEG content increased. Hence, a decrement in the spherulite growth rate was detected in polarizing light microscope (PLM) observation, observing that the PTMEG could enhance the hindrance in the molecular chain to lower the crystallinity of PBT-co-PTMEG copolyester. Moreover, thermal properties and the crystallization rate of PBT-co-PTMEG copolymers can be amended via the regulation of PTMEG contents. [ABSTRACT FROM AUTHOR]

Due to increasing environmental concerns and depletion of petroleum resources, the use of green materials has become popular with garment industry. In the past, natural rubber, which is one of the most prevalent bio‐based elastomers, was used as waterproof coating for many applications due to its inherent elasticity, high tear and abrasion resistance, and hydrophobicity. However, NR has significant drawbacks when applying to garments including its poor adhesion to polyester fabrics and low breathability. Polyurethane, on the other hand, possesses high breathability but relatively poor elasticity. In this study, the fabric coating based on waterborne polyurethane and pre‐vulcanized natural rubber latex was synthesized with the goal to produce fabric for high‐performance applications, which could surpass criteria including water vapor permeability (WVP) (>10 000 g/m2•24hr), water pressure resistance (WPR) (>1000 mmH2O), and stretchability (>300%). The best condition achieved when using 60NR cured for 15 min by using 1.5 phr sulfur could provide WPR value of 4090 mmH2O and WVP of 11 033 g/m2•24hr. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48002. [ABSTRACT FROM AUTHOR]

In this study, materials with low melting temperatures and high toughness are developed for orthopedic applications. A series of an aliphatic copolyester based on sebacic acid (SeA), a green resource, is copolymerized with ethylene glycol, trimesic acid, aminocaproic acid, and adipic acid (AA) to produce poly(ethylene sebacate‐co‐ethylene adipate) (PESA) with various molar ratios through melt polymerization. Thermal characterizations of the PESA copolyesters are tuned with SeA and AA in varying molar ratios, exhibiting a crystalline phase with a lower degree of perfection. The melting point (Tm) and crystallization temperature (Tc) of the copolyesters are observed at 60–70 and 30–40 °C, respectively. Furthermore, a high Young's modulus ranging between 140 and 200 MPa is observed, which could be attributed to the 3D network structure formed by the trimesic acid unit used as a cross‐linking agent. Within the authors' research group, the PESA copolyesters are adopted to reinforce the mechanical properties of a 3D air mesh fabric as a composite application. Also, the highly breathable and low‐weight characteristics of 3D fabric with PESA copolyesters render them suitable for replacing traditional plaster in the future. [ABSTRACT FROM AUTHOR]

Pressure-sensitive adhesives (PSAs) are extensively employed in various applications due to their ability to instantly adhere upon the application of light pressure. Towards a sustainable future is the major driving force for the development of PSAs without solvent. In this study, a two-step melt polycondensation method was used to synthesize a series of copolyesters with varying contents of propanediol (PDO), 2-methyl-1,3-propanediol (MPO), and glycerol. These copolyesters were composed of different molar ratios of PDO/MPO (80/20, 50/50, and 20/80, respectively) and varying glycerol loading in polymer backbone (0, 0.5, and 1.0 mol%, respectively). The influence of the short side group from MPO and the slight crosslinking from glycerol on the thermal and rheological behavior of the copolyesters was investigated. The glass-transition temperature of these copolyesters range from −58.0 to −52.1 °C. Furthermore, the adhesive strength of these copolyesters was evaluated through T-peel and 180° peel testing. The 180° peel strength ranged from 81.1 to 600.6 Pa, while the T-peel strength ranged of 52.5–156.6 Pa. By adjusting the balance of side group and crosslinking content, it was possible to control the relationship between cohesion, adhesion, and tack. This study provides a potential material design for polyester-based and solvent-free PSAs. [ABSTRACT FROM AUTHOR]