Nano-reinforced fillers for natural rubber from bagasse

For natural rubber materials, a strength of Vietnam, the research and manufacture of new rubber materials with high physical and mechanical properties, environmentally friendly without coal black, can be applied in the field of natural rubber. The medical sector as well as other technical rubber products are of great interest. Natural rubber has good mechanical properties but poor oil and heat resistance. In order to increase the applicability of rubber materials, this material is often reinforced with some fillers such as coal black, silica or clay. The reinforcing ability of fillers for rubber depends on particle size, shape, dispersion and ability to interact with rubber. Nano-fillers, ranging in size from 1-100 nm, can significantly improve the mechanical properties of rubber products.

With its excellent and biodegradable properties, Nano cellulose is attractive for applications in many fields such as nanocomposites, surface-modified materials and transparent papers with special functions. Nanocomposite materials using nano cellulose always have some special properties such as high mechanical strength and high thermal properties with light weight and transparency. In addition to improving the mechanical and thermal properties of nanocomposite rubber materials, Nano cellulose also improves a number of other features such as shielding properties of nanocomposites, especially new biodegradable nanocomposite materials such as rubber cellulose nanocomposites are attracting great attention and other smart properties such as antibacterial or bio sensing.

Natural rubber is widely used in many applications and products, such as tires, adhesives, etc. The research and manufacture of new rubber materials with high physical and mechanical properties, are environmentally friendly. The market aims to produce bright colored rubber products applied in the medical field (gloves, finger gloves, ...), sports (insoles, rubber flooring, ...) and in many technical industries. another technique (Figure 1). The research and fabrication of Nano cellulose from bagasse is important in creating new high-value products from readily available, low-cost raw materials. With high physical and mechanical properties, cellulose nanomaterials are ideal reinforcement materials for making environmentally friendly polymer composite materials.

Figure 1. Applications of natural rubber

Through the research process, the team has successfully fabricated cellulose nanocrystals from bagasse by sulfuric acid hydrolysis with diameter 30-70 nm, length 30-70 nm and high crystallinity of 87.9%. Cellulose nanocrystals can also be made by TEMPO oxidation combined with ultrasonic vibration, but the crystallinity is only 66%, lower than that of acid hydrolysis.

Figure 2. Photograph of cellulose samples hydrolyzed in H2SO4 solution for 3 h at different temperatures: (a) 35oC, (b) 45oC, (c) 50oC, (d) 55oC

At the same time, the group has successfully fabricated rubber nanocomposites based on natural rubber (NR)/cellulose nanocrystals by the mixing method in NR latex solution combined with a rolling mill. Cellulose nanocrystals modified with Si69 silane give better mechanical properties than unmodified.

The research team has built 02 technological processes at the laboratory scale, namely the process of making cellulose nanocrystals and the process of making natural rubber/nano cellulose composite. At the same time, 115g of cellulose nanocrystals and 5.1 kg of nanocomposite rubber materials were fabricated.

The project has also published 03 articles, including 02 international articles (01 article in a journal on the list of SCI-E and 01 article in a journal in the list of Scopus) and 01 domestic article. With the obtained results of the topic, the research team wishes to continue to research and perfect the process to soon put these research results into practical application in the near future.

Translated by Quoc Khanh
Link to Vietnamese version