The present study has proposed a straightforward method to improve the reprocessability of modified natural rubber (NR) by blending it with gelatin (GT). The reprocessable characteristics of these blends were evaluated based on their remolding capabilities and mechanical recovery performance. In this method, poly(vinylbenzyl chloride) (PVBC) was first grafted onto NR chains to create graft copolymers known as NR-g-PVBC. The benzyl chloride groups in the graft copolymers were subsequently converted into quaternary ammonium groups, referred to as NR-g-QPVBC. This modification enabled ionic crosslinking when NR-g-QPVBC reacted with ethylenediamine tetraacetic acid. Blends were created by incorporating GT powder into the NR-g-QPVBC latex. The optimal loading level of GT was determined to be 30 wt%, as the resulting film exhibited the highest recovery of tensile properties. Initially, the film's tensile strength was measured at 15 MPa. After being remolded at 160 °C, the tensile strength decreased to 9.3 MPa, resulting in a recovery rate of 60.7% and withstanding a tensile strain of 144%. Although the NR-g-QPVBC/GT films could be remolded, their tensile properties declined with increasing remolding cycles. Therefore, this work demonstrated a practical method for producing NR-based films that could be reshaped through hot-pressing after being formed into products, increasing their reusability.

As polyvinyl chloride (PVC) films are hard and brittle in a low-temperature environment, aliphatic dibasic acid ester plasticizers with different acid chain lengths were fabricated, i.e. di(2-ethylhexyl) adipate (DOA), di(2-ethylhexyl) sebacate (DOS) and dioctyl dodecanedioate (DOD), and their effects on the cold-resistant properties of PVC were investigated using experiments and molecular dynamics (MD) simulations. The brittleness temperature and tensile properties of plasticizers/PVC are negatively related to the acid chain length of the aliphatic dibasic acid esters. The brittleness temperatures of the three systems are all below –50 °C. In-situ low-temperature tensile tests and aging tests indicate that DOA/PVC exhibits the best cold resistance and stability. MD simulations further reveal that the best compatibility between DOA and PVC is attributed to its strong binding energy and weak hydrogen bonding interactions, while van der Waals forces are dominant in DOS/PVC and DOD/PVC. This study elucidates the structure-property relationship between aliphatic dibasic acid ester plasticizers and PVC from the perspective of molecular interactions, and provides insights into the design of cold-resistant PVC plasticizers.

Powder-free natural rubber gloves for chemical migration resistance of food-contact grade are prepared using a variety of fillers, including ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), aluminum silicate (AS), and barium sulfate (BS)-filled natural rubber (NR), respectively. The properties of NR gloves, including mechanical, dynamic mechanical, and thermal properties, were investigated. Furthermore, the overall migration test of NR gloves was conducted according to the regulations for food contact gloves (EU Regulation No. 10/2011), using 3% acetic acid as the simulant. Among the fillers studied, the plate-like particles of AS facilitated the most effective filler-rubber interactions and reinforcement in AS-filled natural rubber (NR/AS). Consequently, the highest crosslink density, force at break, and damping properties of NR gloves were achieved by applying AS in the NR matrix. Moreover, the lowest overall migration level was observed for NR/AS with a value of 5.35 mg/dm², which complies with EU Regulation (overall migration of food simulants shall not exceed 10 mg/dm²). Therefore, NR gloves filled with AS are suitable for food-contacting NR gloves.

In this work, a PDMS spinning technique is developed and enables the continuous production of a filament with a circular cross-section (~500 μm diameter). The production of continuous silicone polymer filaments can be useful in the textile field to provide new properties in applications such as weaving, knitting or composite reinforcement. The method involves injecting the pre-polymer and curing agent mixture into a heated oil bath (202–215 °C) to simultaneously shape and cure the PDMS. The morphological and mechanical properties of the filament are studied regarding the production parameters (formulation, needle diameter, bath temperature, conveyor belt speed). The most homogeneous filament is produced at the highest temperature (215°C) and conveyor belt speed (13.6 m∙min^–1). When subjected to cyclic mechanical stress, the PDMS filament produced exhibits stable mechanical behavior, making it suitable for a wide range of applications.

This work reported a practical approach to turning conventional natural rubber (NR) into a thermally healable rubber. 4-vinylbenzyl chloride was first polymerized in the NR latex to yield graft copolymers of NR and poly(vinylbenzyl chloride), NR-g-PVBC. The cutting and rejoining process was used to study the healing ability of latex film. The healing behavior was observed after the reassembled film was heated at 100 °C for 1 h and then allowed to heal continuously at room temperature (RT). The healed film displayed a 58.44% regain of the tensile strength (4.57 MPa) after being allowed to recover at RT for 72 h. Additionally, the chloromethyl moieties in the NR-g-PVBC could be converted into quaternary ammonium (QA) groups by reaction with trimethylamine, producing the quaternized NR-g-PVBC (NR-g-QPVBC). Ionic crosslinking of the NR-g-QPVBC film was achieved by incorporating sodium tripolyphosphate (STPP). The latex film had a tensile strength of 15.32 MPa and could withstand a strain of 868% when ionically cured with 2 phr of STPP. After the healing process, the cured film showed a healing efficiency of 49.67% in tensile strength (7.61 MPa). Furthermore, a suturing test was performed to investigate the feasibility of developing a suture training pad from the corresponding cured film. The film’s ability to heal with heat assistance was its significant practical advantage, enhancing its realism and mimicking the healing process in human skin.