Synthesis and chemical modification of crystalline nanocellulose to reinforce natural rubber composites

Abstract

Potential of crystalline nanocellulose (CNC), as green reinforcing filler, has been evaluated for the preparation of natural rubber (NR) composites. CNC is derived from a natural source (ramie fiber) and its surface is modified with different organosilanes to strengthen the rubber‐filler interaction at the interface. It is found that, although at 2.5 phr (parts per hundred parts of rubber) loading of CNC the mechanical property of the NR composites is improved, it deteriorates at 5 phr loading. Surface modification of CNC by organosilanes is found very useful to overcome this issue. The modulus values at low strain become almost 1.5 to 2 times higher while tensile strength becomes 2.5 times higher for the modified CNC filled composites relative to those of CNC filled composites at 5 phr loading. These results are corroborated with a morphological study, where a very good state of dispersion of CNC particles is found in the surface‐modified CNC filled composites. Moreover, the particle size of CNC becomes almost half, in respect to that of unmodified CNC particles, upon surface modification by organosilane. The reinforcement effect delivered by CNC and surface‐modified CNC is also reflected by a small positive shift in Glass Transition Temperature (Tg) in differential scanning calorimetry study.

Surface Modified Nanocellulose and Its Reinforcement in Natural Rubber Matrix Nanocomposites: A Review

“…In addition, non-polar natural rubber also restricted the well-dispersion of polar CNC in the natural rubber matrix. This problem was overcome by the surface modification of CNC with (3-Aminopropyl)triethoxysilane (APTES), where the polar nature of the CNC was reduced after modification [ 54 ]. Moreover, aliphatic chains from APTES could coat over the surface of CNC and improve its compatibility with natural rubber.…”

“…The crystallinity of the nanocellulose was reduced by chemical modification and subsequently weakened its reinforcement potential in polymer composites [64]. However, Singh et al [54] proved that the silylation treatment did not affect the crystallinity of the CNC adversely as the modification only occurred mostly at the surface of the CNC. In a study by Somseemee et al [55], the crystallinity of the CNF modified by Bis-(triethoxysilylpropyl) tetrasulfide (TESPT) showed a slight decrease from 74.3% to 69.5%.…”

Modified nanocrystalline cellulose partially replaced carbon black to reinforce natural rubber composites

“…10 However, the researchers found that nanocellulose was a widely sourced, renewable and biodegradable green material with high strength, high modulus, crystallinity, and other characteristics, which has the potential to be an green filler for reinforcing polymer composites. [11][12][13][14] In recent years, the number of publications and literatures on nanocellulose has increased year by year. [15][16][17][18] Among them, there were many studies on nanocellulose reinforced rubber composites.…”

The use of Bis‐(3‐triethoxysilylpropyl) tetrasulphane for surface modification of silica, ferrite and kenaf fiber filled natural rubber composites; comparison of aqueous solvent deposition, dry blend and integral blend methods

“…Integral blending method is widely used in the rubber‐filler system because of its simplicity and possible cost advantages 26–29 . In this method, TESPT is used as a simple additive during the compounding of rubber on two‐roll mixing mill or internal mixer.…”