Preparation and characterization of silicone rubber cured via catalyst-free aza-Michael reaction

This research emphasizes the importance of the acid cleaning prior to the phosphate development on high-strength steel rods. It compares the phosphate properties achieved after different acid-pickling conditions. The most common inorganic acids were considered in this study. Additionally, taking into account the environmental and safety concerns of these acids, the assessment of a less harmful organic acid is presented. This study revealed significant differences in the coating morphology and chemical composition whereas no great changes were found in terms of the coating weight or porosity. Thus, hydrochloric and sulfuric acid promote the growth of a Fe-enriched phosphate layer with a less conductive character that is not developed after the pickling with phosphoric acid. The phosphate developed after the citric acid pickling is comparable to that developed after the inorganic acids although with a porosity slightly higher. The temperature of the citric acid bath is an important parameter that affects to the phosphate appearance, composition, and porosity.

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Preparation and characterization of high strength and high modulus PVA fiber via dry‐wet spinning with cross‐linking of boric acid

Journal of Applied Polymer Science ◽

10.1002/app.51394 ◽

2021 ◽

pp. 51394

Author(s):

Xinqiu Hong ◽

Junwei He ◽

Liming Zou ◽

Yanli Wang ◽

Yan Vivian Li

Keyword(s):

Boric Acid ◽

High Strength ◽

Wet Spinning ◽

Cross Linking ◽

High Modulus ◽

Pva Fiber

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Facile Synthesis and Characterization of Palm CNF-ZnO Nanocomposites with Antibacterial and Reinforcing Properties

International Journal of Molecular Sciences ◽

10.3390/ijms22115781 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5781

Author(s):

Janarthanan Supramaniam ◽

Darren Yi Sern Low ◽

See Kiat Wong ◽

Loh Teng Hern Tan ◽

Bey Fen Leo ◽

...

Keyword(s):

Plant Biomass ◽

Cellulose Nanofibers ◽

High Strength ◽

Salmonella Typhi ◽

Particle Sizes ◽

Mechanical Reinforcement ◽

Uniform Size ◽

Preparation Methods ◽

Potential Applications

Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CNF-zinc oxide (CNF-ZnO) nanocomposite with dual antibacterial and reinforcing properties via a facile and efficient ultrasound route. We characterized and examined the antibacterial and mechanical reinforcement performances of our ultrasonically induced nanocomposite. Based on our electron microscopy analyses, the ZnO deposited onto the nanofibrous network had a flake-like morphology with particle sizes ranging between 21 to 34 nm. pH levels between 8–10 led to the formation of ultrafine ZnO particles with a uniform size distribution. The resultant CNF-ZnO composite showed improved thermal stability compared to pure CNF. The composite showed potent inhibitory activities against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative Salmonella typhi (S. typhi) bacteria. A CNF-ZnO-reinforced natural rubber (NR/CNF-ZnO) composite film, which was produced via latex mixing and casting methods, exhibited up to 42% improvement in tensile strength compared with the neat NR. The findings of this study suggest that ultrasonically-synthesized palm CNF-ZnO nanocomposites could find potential applications in the biomedical field and in the development of high strength rubber composites.

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