Low cost and high durability have made Portland cement the most widely‐used building material, but benefits are offset by environmental harm of cement production contributing 8–10% of total anthropogenic CO2gas emissions. High sulfur‐content materials (HSMs) are an alternative that can perform the binding roles as cements with a smaller carbon footprint, and possibly superior chemical, physical, and mechanical properties. Inverse vulcanization of 90 wt% sulfur with 10 wt% canola oil or sunflower oil to yield CanS or SunS, respectively. Notably, these HSMs prepared at temperatures ≤180 °C compared to >1200 °C hours for Portland cement CanS was combined with 5 wt% fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBFS), or metakaolin (MK) to give composites CanS‐FA, CanS‐SF, CanS‐GGBFS, and CanS‐MK, respectively. The analogous protocol with SunS likewise yielded SunS‐FA, SunS‐SF, SunS‐GGBFS, and SunS‐MK. Each of these HSMs exhibit high compressive mechanical strength, low water uptake values, and exceptional resistance to acid‐induced corrosion. All of the composites also exhibit superior compressive strength retention after exposure to acidic solutions, conditions under which Portland cement undergoes dissolution. The polymer cement‐pozzolan composites reported herein may thus serve as greener alternatives to traditional Portland cement in some applications.
Here are reported composites made by crosslinking unsaturated units in canola, sunflower, or linseed oil with sulfur to yield
- Award ID(s):
- 1708844
- NSF-PAR ID:
- 10456416
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Polymer Science
- Volume:
- 58
- Issue:
- 16
- ISSN:
- 2642-4150
- Page Range / eLocation ID:
- p. 2259-2266
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
more » « less
Abstract Rancid animal fats unsuitable for human or animal food production represent low‐value and abundant, yet underexploited organic chemical precursors. The current work describes a strategy to synthesize high sulfur‐content materials (HSMs) that directly utilizes a blend of partially hydrolyzed chicken fat and plant oils as the organic comonomers, following up on analogous reactions using brown grease in place of chicken fat. The reaction of sulfur and chicken fat with either canola or sunflower oil yielded crosslinked polymer composites CFSxor GFSx, respectively (
x = wt% sulfur, varied from 85%–90%). The composites exhibited compressive strengths of 24.7–31.7 MPa, and flexural strengths of 4.1–5.7 MPa, exceeding the value of established construction materials like ordinary Portland cement (compressive strength ≥17 MPa required for residential building, flexural strength 2–5 MPa). The composites also exhibited thermal stability up to 215–224 °C. The simple single‐step protocol described herein represents a way to upcycle an affordable and previously unexploited animal fat resource to form structural composites via the atom economical inverse vulcanization mechanism. -
more » « less
Abstract A three‐stage route to chemically upcycle post‐consumer poly(ethylene terephthalate) (PET) to produce high compressive strength composites is reported. This procedure involves initial glycolysis with diethylene glycol to produce a mixture (GPET) comprising oligomers of 2–7 terephthalate units followed by trans/esterification of GPET with fatty acid chains supplied by brown grease, an agricultural by‐product of animal fat of relatively low nutritional or fuel value. This process yields PGB comprising a mixture of mono‐terephthalate ester derivatives. The olefin units provided by unsaturated fatty acid chains in brown grease were crosslinked by an inverse vulcanization reaction with elemental sulfur to give composites GBS
x (x = wt% S, varied from 80%–90%). The compressive strengths of GBS80(27.5 ± 2.6 MPa) and GBS90(19.2 ± 0.8 MPa) exceed the compressive strength required of ordinary Portland cement (17 MPa) for its use in residential building foundations. The current route represents a way to repurpose waste plastic, energy sector by‐product sulfur, and agricultural by‐product brown grease to give high strength composites with mechanical properties suggesting their possible use to replace less sustainably sourced legacy structural materials. -
null (Ed.)The search for alternative feedstocks to replace petrochemical polymers has centered on plant-derived monomer feedstocks. Alternatives to agricultural feedstock production should also be pursued, especially considering the ecological damage caused by modern agricultural practices. Herein, l -tyrosine produced on an industrial scale by E. coli was derivatized with olefins to give tetraallyltyrosine. Tetraallyltyrosine was subsequently copolymerized via its inverse vulcanization with industrial by-product elemental sulfur in two different comonomer ratios to afford highly-crosslinked network copolymers TTSx ( x = wt% sulfur in monomer feed). TTSx copolymers were characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). DMA was employed to assess the viscoelastic properties of TTSx through the temperature dependence of the storage modulus, loss modulus and energy damping ability. Stress–strain analysis revealed that the flexural strength of TTSx copolymers (>6.8 MPa) is more than 3 MPa higher than flexural strengths for previously-tested inverse vulcanized biopolymer derivatives, and more than twice the flexural strength of some Portland cement compositions (which range from 3–5 MPa). Despite the high tyrosine content (50–70 wt%) in TTSx , the materials show no water-induced swelling or water uptake after being submerged for 24 h. More impressively, TTSx copolymers are highly resistant to oxidizing acid, with no deterioration of mechanical properties even after soaking in 0.5 M sulfuric acid for 24 h. The demonstration that these durable, chemically-resistant TTSx copolymers can be prepared from industrial by-product and microbially-produced monomers via a 100% atom-economical inverse vulcanization process portends their potential utility as sustainable surrogates for less ecofriendly materials.more » « less
-
Herein we report a method for the chemical recycling of poly(ethylene terephthalate) (PET) by a three-stage process employing sustainably-sourced organic materials and industrial byproduct sulfur. In this protocol, PET was subject to glycolysis with diethylene glycol to yield low molecular weight oligomers with hydroxyl end groups. The glycolyzed PET (GPET) was then reacted with oleoyl chloride to yield esterified PET (EPET) containing vulcanizable olefin units. The oligomers constituting GPET and EPET were elucidated by MALDI-TOF spectrometry. EPET underwent inverse vulcanization with elemental sulfur (90 wt%) for 35 min or 24 h to yield xPES or mPES, respectively. The composition, thermal, morphological, thermal and mechanical properties were characterized. The composites exhibited good to excellent mechanical properties that were improved significantly by extending the reaction time from 35 min used to prepare xPES (compressive strength = 10.5 MPa, flexural strength = 2.7 MPa) to 24 h used to prepare mPES (compressive strength = 26.9 MPa, flexural strength = 7.7 MPa). Notably, the compressive and flexural strengths of mPES represent 158% and 208% of the values required for residential building foundations made from traditional materials such as ordinary Portland cement. The three-stage approach delineated herein thus represents a way to mediate chemical recycling of waste plastic with green coreagents to yield composites having mechanical properties competitive with existing commercial structural materials.more » « less
