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.
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Use of fly ash as eco-friendly filler in synthetic rubber for tire applications
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 resistance
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- Award ID(s):
- 1650460
- NSF-PAR ID:
- 10079055
- Date Published:
- Journal Name:
- Journal of cleaner production
- Volume:
- 206
- ISSN:
- 0959-6526
- Page Range / eLocation ID:
- 374 - 382
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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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
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Fly ash consists of mainly silt-size spherules that form during high-temperature coal combustion, such as in steam locomotives and coal-burning power plants. In the eastern USA, fly ash was distributed across the landscape atmospherically beginning in the late 19th century, peaking in the mid-20th century, and decreasing sharply with implementation of late 20th century particulate pollution controls. Although atmospheric deposition is limited today, fly ash particles continue to be resedimented into alluvial and lacustrine deposits from upland soil erosion and failure of fly ash storage ponds. Magnetic fly ash is easily extracted and identified microscopically, allowing for a simple and reproducible method for identifying post-1850 CE (Common Era) alluvium and lacustrine sediment. In the North Carolina Piedmont, magnetic fly ash was identified within the upper 50 cm at each of eight alluvial sites and one former milldam site. Extracted fly ash spherules have a magnetite or maghemite composition, with substitutions of Al, Si, Ca, and Ti, and range from 3–125 µm in diameter (mainly 10–45 µm). Based on the presence of fly ash, post-1850 alluvial deposits are 15–45 cm thick in central North Carolina river valleys (<0.5 km wide), ~60% thinner than in central Illinois valleys of similar width. Slower sedimentation rates in North Carolina watersheds are likely a result of a less agricultural land and less erodible (more clayey) soils. Artificial reservoirs (Lake Decatur, IL) and milldams (Betty’s Mill, NC), provide chronological tests for the fly ash method and high-resolution records of anthropogenic change. In cores of Lake Decatur sediments, changes in fly ash content appear related to decadal-scale variations in annual rainfall (and runoff), calcite precipitation, land-use changes, and/or lake history, superimposed on longer-term trends in particulate pollution.more » « less
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To promote the sustainable development of eco-efficient calcium sulfoaluminate (CSA) cements through the partial replacement of the CSA clinker with supplementary cementitious waste products, the effects of coal fly ashes on the early-age and mature-age properties of a calcium sulfoaluminate (CSA)-based cement paste were investigated. The impacts of both Class C and Class F fly ashes on the rheological properties, hydration kinetics, and compressive strength development of CSA cement paste were studied. Rheology-based workability parameters, representing the rate of loss of flowability, the rate of hardening, and the placement limit, were characterized for the pastes prepared with fixed water-to-cement (w/c) and fixed water-to-binder (w/b) ratios. The results indicate a slight improvement in the workability of the CSA paste by fly ash addition at a fixed w/b ratio. The isothermal calorimetry studies show a higher heat of hydration for the Class C fly ash-modified systems compared to the Class F-modified systems. The results show that fly ash accelerates the hydration of the calcium sulfoaluminate cement pastes, chiefly due to the filler effects, rather than the pozzolanic effects. In general, ettringite is stabilized more by the addition of Class F fly ash than Class C fly ash. Both fly ashes reduced the 1-day compressive strength, but increased the 28-day strength of the CSA cement paste; meanwhile, the Class C modified pastes show a higher strength than Class F, which is attributed to the higher degree of reaction and potentially more cohesive binding C-S-H-based gels formed in the Class C fly ash modified systems. The results provide insights that support that fly ash can be employed to improve the performance of calcium sulfoaluminate cement pastes, while also enhancing cost effectiveness and sustainability.more » « less
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Accepted Manuscript1.0
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