Preparation and properties of natural rubber reinforced with polydopamine-coating modified carbon nanotubes

Abstract

IntroductionNR is one of the most important nature polymers, which is widely used as the elastomeric matrix of various materials, including conveyor belts, sealing rings, tires, etc. In order to meet the requirements of the use of tires, NR composites must have the following two properties: (1) good mechanical properties, in order to undergo cyclic loading and strains in actual use, (2) good thermal conductivity and electrical conductivity, in order to export the heat or static electricity effectively and timely. However, traditional fillers (such as carbon black, silica, alumina, etc.) cannot improve both aspects simultaneously, though the high surface carbon blacks may improve both mechanical properties and electrical conductivity, but the precondition is that a relative large amount of high surface carbon black must be added, this may adversely affect the processing performance of the composites. Recently, the carbon nanotubes (CNTs) have become a hot spot in various research fields for their unique structure and outstanding performances [1,2]. High mechanical properties (tensile strength is 50 GPa, Young modulus is ~5 TPa) and good conductivity (electrical conductivity is ~10 7 s/m, thermal Abstract. Multi-walled carbon nanotubes (MWCNTs) were functionalized by polydopamine (PDA)-coating and mixed with natural rubber (NR) via latex compounding. Compared with pristine MWCNTs, the surface of MWCNT-PDA was covered by an amorphous and nanometer-scale PDA layer which had a large amount of oxygenic and nitric functional groups. So the MWCNT-PDA showed a perfect dispersion in NR matrix. The tensile strength of NR/MWCNT-PDA (5 phr) composites is 28.6 MPa, compared with the pure NR, which increased by 42%. For the electrical properties, when the content of MWCNT-PDA or MWCNTs is 2 phr, the volume resistivity of NR/MWCNT-PDA composites falls to about 2.7·10 9 Ω·cm, compared with 3.3·1013 Ω·cm of NR/MWCNT composites. The thermal conductivity of NR composites increased only by 28.2% when 5 phr MWCNT-PDA was added. A model proposed by Nan was used to calculate the thermal conductivity of NR/MWCNT composites, and the calculated values were compared with the experimental values, the results showed that the interface thermal resistance is the main reason why MWCNTs could not significantly increase the thermal conductivity of natural rubber.

Poly(hexane succinate) plasticizer designed for poly(vinyl chloride) with a high efficiency, nontoxicity, and improved migration resistance

“…Furthermore, the motion of long alkyl chains of PHS also created more free volume in the polymer, which played a certain role in the lubrication. Tensile testing and hardness testing, which could be used to determine the mechanical properties of materials were used to investigate the polymer plasticity . With increasing PHS amount, its effects on three kinds of mechanical properties of PVC were different.…”

“…Tensile testing and hardness testing, which could be used to determine the mechanical properties of materials were used to investigate the polymer plasticity. 23,24 With increasing PHS amount, its effects on three kinds of mechanical properties of PVC were different. The elongation at break and hardness of PVC-PHS decreased first and then increased with increasing PHS, whereas the tensile strength showed a reverse trend.…”

Mechanical Reinforcement in Nylon 6 Nanocomposite Fiber Incorporated with Dopamine Reduced Graphene Oxide

“…The formed PDA surface possesses highly reactive functional groups, and it can be used to enhance the compatibility of nanofillers and polymers. Thus, DA has emerged as a functional modifier of nanofillers in the field of polymer reinforced nanocomposites [ 19 , 20 , 21 , 22 ]. Y.L.…”

“…Lu et al incorporated PDA-modified, multi-walled carbon nanotubes (MWCNTs) into natural rubber (NR) via latex compounding. The modified carbon nanotubes showed excellent dispersion in the matrix, increasing the tensile strength of the composite by 42% [ 20 ]. Y. Fang et al prepared polyimide (PI) with polydopamine functionalization boron nitride nanosheets composite fiber by in situ polymerization, and the results indicated that the tensile strength and modulus of the composite fiber were a significant improvement with the addition of modified boron nitride nanosheets (0.5 wt% content) [ 21 ].…”

Double‐layer modified silica with potential reinforcement for solution polymerized styrene‐butadiene rubber/butadiene rubber composite

“…However, there are usually poor compatibility and interface adhesion between nano‐SiO 2 and rubber matrix, which results in poor dispersibility of nano‐SiO 2 in the rubber matrix and hinders its application in tire industry 8–10 . This drawback, fortunately, could be eliminated by surface‐capping nano‐SiO 2 with silane coupling agent, 11,12 ionic liquid, and compatibilizer 13–20 . For example, Sung‐seen choi 21 found that chloroprene rubber could improve the dispersion of silica in natural rubber, which is attributed to the hydrogen bond interaction between silicon hydroxyl and chloride group.…”