Reinforcing fillers are necessary in rubber compounding to aid in enhancing the
mechanical properties of the compound for various applications. Carbon black (CB) is currently
the most common reinforcing filler used in tire compounding. Lignin, an amorphous polyphenolic
material derived from plants and a by-product of the pulp and paper industry, is also an attractive
material that can serve as a dispersant and as a reinforcing filler. This paper evaluates the
interactions between styrene-butadiene rubber and reinforcing fillers with an electron-rich π-
system, such as lignin and CB, in the presence of a graft copolymer (PB-g-PPFS) of PB and
electron-deficient 2,3,4,5,6-pentafluorostyrene (PFS). The interactions are attributed to areneperfluoroarene
interactions between the electron-deficient π-system of the polyperfluoroarene
grafts and the electron-rich π-system of lignin and/or CB particles. The effects of improved fillerrubber
interactions on mechanical properties and dynamic mechanical properties are analyzed.
This paper will demonstrate the use of PB-g-PPFS as a coupling agent in rubber compounds to
enhance the interaction between the filler, lignin and lignin-carbon black hybrid filler, and the
rubber matrix to achieve a reduction in the hysteresis loss and enhanced filler dispersion.
more »
« less
Exploiting arene-perfluoroarene interactions for dispersion of carbon black in rubber compounds
Coupling agents are intended to promote filler dispersion by providing a bridge between the filler and
the rubber phase. This study investigated the ability of a novel physical coupling agent, poly(butadienegraft-pentafluorostyrene)
in a mixture with polypentafluorostyrene, to improve rubber-filler interactions
and suppress filler-filler networking in carbon-black-reinforced styrene-butadiene rubber (SBR), and
thereby decrease hysteresis. The electron-rich aromatic rings of carbon black are involved in areneperfluoroarene
interactions with the electron-poor pentafluorostyrene aromatic rings of the coupling
agent. The SBR chains in the rubber compound have an affinity for the polybutadiene backbone of the
coupling agent. The interactions between carbon black and the coupling agent were analyzed using
Raman spectroscopy, transmission electron microscopy, zeta potential measurements, surface area
measurements, and scanning electron microscopy. Filler flocculation analysis showed that the coupling
agent improves the dispersion and lowers the energy of dissipation. The hysteresis loss, quantified in
terms of loss tangent values at 60 C, was reduced by up to 12% due to the coupling agent's promotion of
better filler-rubber interactions. The influence of the PPFS graft length was also studied.
more »
« less
- Award ID(s):
- 1650460
- NSF-PAR ID:
- 10078730
- Date Published:
- Journal Name:
- Polymer
- Volume:
- 148
- ISSN:
- 0032-3861
- Page Range / eLocation ID:
- 247-258
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
more » « less
Abstract Incorporation of nanofillers (such as silica) into elastomer matrix is the most common strategy to prepare high‐performance rubber products. However, the poor dispersion of nanofillers in non‐affinity rubber materials and the weak interfacial interaction significantly limit the processing and mechanical properties. To reduce the polarity difference and enhance the interfacial interaction between silica and styrene butadiene rubber (SBR), we prepared a hydroxyethyl acrylate‐grafted SBR (SBR‐g‐HEA) through the redox initiator system, and subsequently fabricated SBR‐g‐HEA/silica nanocomposites by simple mechanical blending. The effects of reaction conditions on the grafting rate were studied in detail. ATR‐FTIR and1H‐NMR collectively confirmed the successful grafting of HEA groups on SBR molecular chains, and the grafting fraction could be regulated from 0% to 2.5%. Scanning electron microscope (SEM) and rubber processing analyzer (RPA) showed that the incorporation of HEA could significantly improve the dispersion of silica nanoparticles in SBR matrix. Notably, the resulting SBR‐g‐HEA exhibited significantly enhanced attributes when compared to their unmodified counterparts, including superior mechanical properties, improved wear resistance, and reduced heat generation. The strategy proposed here provided insights toward the fabrication of non‐affinity rubber/filler nanocomposites for high‐performance rubber products and green tire.
-
A byproduct of the power generation industries, fly ash can be used as a potential filler in many commercial products including rubber-based products. Reusing the fly ash in this manner is an efficient way to help prevent air pollution which occurs if such particles are released freely to the atmosphere. The reinforcement efficiency of fly ash for partial replacement of carbon black and silica fillers in styrenebutadiene rubber compounds was investigated in this work. The total content of fillers was held constant at 50 phr (weight ratio of filler to rubber was 0.5) when not using silica fillers at all, and 54 phr when using 4 phr carbon black only with silica fillers, while the content of fly ash increased from 0 to 10 phr. In the evaluation of the rubber compounds, the focus was the mechanical properties and adhesion of steel reinforcement cords to the styrene-butadiene rubber compounds. Adhesion between the compounds and steel wire reinforcement was measured for assessing efficacy of adding fly ash to the rubber compounds in tire applications. Ball mill treatment was used to reduce the size of the fly ash particles while also modifying their surface topography. The comparisons of untreated and ball mill treated fly ash filled rubber compounds and rubber compounds containing different fillers were accomplished subsequently. The results revealed that the partial addition of up to 10 phr fly ash to rubber compounds resulted in increases in elongation at break, adhesion to reinforcement steel cord, wet-grip, as well as lower rolling resistancemore » « less
-
A coarse-grained model has been built to study the effect of the interfacial interaction between spherical filler particles and polymer on the mechanical properties of polymer nanocomposites. The polymer is modeled as bead-spring chains, and nano-fillers grafted with coupling agent are embedded into the polymer matrix. The potential parameters for polymer and filler are optimized to maximally match styrene-butadiene rubber reinforced with silica particles. The results indicated that, to play a noticeable role in mechanical reinforcement, a critical value exists for the grafting density of the filler–polymer coupling agent. After reaching the critical value, the increase of grafting density can substantially enhance mechanical properties. It is also observed that the increase of grafting density does not necessarily increase the amount of independent polymer chains connected to fillers. Instead, a significant amount of increased grafting sites serve to further strengthen already connected polymer and filler, indicating that mechanical reinforcement can occur through the locally strengthened confinement at the filler–polymer interface. These understandings based on microstructure visualization shed light on the development of new filler polymer interfaces with better mechanical properties.more » « less
-
more » « less
ABSTRACT Hyperbranched aromatic polyamide (HBP) was grafted successfully onto carbon fibers (CFs) on the basis of solution polymerization to enhance the interfacial adhesion strength of CF‐reinforced epoxy resin composites. The microstructure and interfacial properties of the CFs before and after decoration were researched. The results indicate that HBP was deposited uniformly onto the CFs with γ‐aminopropyl triethoxysilane as the bridging agent. The active groups, roughness, and surface energy of the modified fiber [hyperbranched aromatic polyamide grafted carbon fiber (CF–HBP)] increased visibly in comparison with those of the untreated CFs. The CF–HBP composites revealed simultaneous remarkable enhancements (65.3, 34.3, and 84.8%) in their interfacial shear strength, flexural strength, and modulus, respectively; this was attributed to the improvement in the fiber–epoxy interface through enhanced chemical interactions, mechanical interlocking, and wettability. These agreed with the scanning electron microscopy observations from the fracture surface morphologies of the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.
2019 ,136 , 47232.
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- The DOI is not currently available.
