Heliang Wang,Fanrong Meng,Mingyuan Yi,Lin Fang,Zhifen Wang,Shoujuan Wang
Natural rubber latex (NRL) is commonly employed to manufacture medical protective appliances. However, the characteristics of weakness and fragility of NRL membranes limit their further application. To achieve excellent strength and damage-resistance of the rubber membrane, this work reported a facile core–shell structure construction strategy via self-assembly with modified sodium lignosulfonate (MSLS) and NRL to create a tough membrane. The double network can be formed after introducing polyamide epichlorohydrin resin (PAE) into the NRL membrane. Specifically, the first robust MSLS-PAE network can break in advance to dissipate applied energy, thereby achieving high fracture energy and tensile strength of ~111.51 kJ m−2and ~37 MPa, respectively, which overtakes numerous soft materials. This work facilitates more studies on latex/lignin-based products with high performance and good stability for the functional application of biopolymer.Keywords:natural rubber latex membrane;self-assembly;double network;toughening;sodium lignosulfonate
In this study, a stable antibacterial poly(styrene-co-butyl acrylate) (poly(St-co-BA)) nano-latex was prepared in the presence of a dioctyldimethylammonium chloride (D821)-CTAB mixed surfactant and a novel bis -unsaturated Gemini comonomer (i.e., α, ω -hexanediyl bis (dimethyl methacrylamidopropyl ammonium bromide) (G MAP-6-MAP )) using a feasible and mild semicontinuous technology. The effects of the emulsifiers and G MAP-6-MAP on the properties and antibacterial activities of poly(St-co-BA) coatings were systematically investigated. The results indicate that an optimal monodispersed stable nanoemulsion was obtained with Dw = 58.24 nm and PDI = 0.026, the emulsifier amount was 3.75% (D821/CTAB = 4:1), and the G MAP-6-MAP amount was 1.5%. CTAB improved the stabilities and antibacterial activities of the poly(St-co-BA) nanoemulsions. The incorporation of G MAP-6-MAP into poly(St-co-BA) can enhance the antibacterial activity, improve the thermal stability of latex films, as well as the consistency among the chain segments, and decrease the roughness of latex films. This nanoemulsion exhibits effective antibacterial activity with MBCs of 2 μg·mL − 1 against Staphylococcus aureus and 16 μg·mL − 1 against Escherichia coli . The sterilization rates of the optimized latex film reached 100% against S. aureus and 98.74% against E . coli , which indicated that this latex film could be utilized as an outstanding antibacterial coating.
He Gong,Zhifen Wang,Lin Fang,Jianhe Liao,Kai Liang,Zhiquan Wen
Natural latex films with high mechanical properties and low water-soluble protein content are hot spots of research in the rubber latex industry. In this paper, a simple method to prepare a natural latex film with high strength , low water-soluble protein content, antioxidant, antimicrobial and good biocompatibility is presented. Firstly, hydroxyapatite (HA) was organically modified using isocyanate and tannic acid , and the composite adhesive film was prepared by blending with natural rubber latex (NRL) emulsion. A filler framework network structure based on multiple hydrogen bonding interactions was constructed in the rubber matrix, which effectively limited the aggregation of fillers, significantly improved the mechanical properties of NRL adhesive films, and greatly reduced the water-soluble protein content. When the modified hydroxyapatite (mHA) was added at 1.2 wt%, the tensile strength and tear strength of mHA/NRL film increased by 32.47 % and 53.52 %, and the water-soluble protein content decreased by 92.25 % compared with pure NRL film. In addition, the modified HA endowed the NRL film with excellent antioxidant and antibacterial properties and good biocompatibility. The present work provides a new strategy for the preparation of natural latex films with multifunctionality and opens up new avenues for the application of latex in the fields of papermaking, film products, and biomedicine.
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