Center for Sustainable Polymers (CSP)
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The mission of the Center for Sustainable Polymers (CSP) is to transform how plastics are made and unmade through innovative research, engaging education, and diverse partnerships that together foster environmental stewardship. CSP participants aim to design, prepare, and implement polymers derived from renewable resources for a wide range of advanced applications, and to promote future economic development, energy efficiency, and environmental sustainability in the emergent area of biobased products.
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Browsing Center for Sustainable Polymers (CSP) by Author "Bates, Frank S"
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Item Step-Growth Polyesters with Biobased (R)-1,3-Butanediol(2020-08-26) DeRosa, Christopher A; Kua, Xiang Qi; Bates, Frank S; Hillmyer, Marc A; hillmyer@umn.edu; Hillmyer, Marc A; University of Minnesota, Department of ChemistryThese files contain primary data along with associated output from "Step-Growth Polyesters with Biobased (R)-1,3-Butanediol" by Hillmyer et al. We present the synthesis and characterization of polymers containing 1,3-butanediol, also known as butylene glycol. Butylene glycol (BG) can be prepared from petroleum or sugar-based feedstocks. Petrol-based BG (petrol-BG) is isolated as a racemic mixture, whereas the bio-based BG from sugar that we utilized (Bio-BG), is enantiopure upon purification (>99.7%). In the presence of a titanium catalyst, polyesters were prepared by transesterification polymerization between petrol- or Bio-BG and various aliphatic and aromatic diacid derivatives. Polymers were analyzed by size-exclusion chromatography (SEC), 1H NMR and 13C NMR spectroscopies, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The synthesized polyesters were statistical in nature, according to 13C NMR spectroscopy, a result of the asymmetric nature of the BG-starting material. As a result, many of the polyesters were amorphous in nature with low thermal glass transitions (Tg) and no melting points (Tm). In many of the polyester derivatives, the racemic petrol-based and enantiopure bio-based BG polymers were nearly identical in thermal performance. Differences arose in semi-crystalline polyesters with long, aliphatic backbones (e.g., 1,14-tetradecanediocic acid; C14 diacid) or regioregular 4-hydroxybenzoate polyesters. This suggests the polymer microstructure (statistical versus sequenced) and the optical activity (racemic versus enantiopure) are important determinates in establishing the structure-property relationships in BG-containing polyesters. This work establishes synthetic protocols and the foundation for materials based on BG-containing polymers.Item Supporting data for Consequences of Grafting Density on the Linear Viscoelastic Behavior of Graft Polymers(2018-02-06) Haugan, Ingrid N; Maher, Michael J; Chang, Alice B; Lin, Tzu-Pin; Grubbs, Robert H; Hillmyer, Marc A; Bates, Frank S; bates001@umn.edu; Bates, Frank SThese files contain data along with associated output from instrumentation supporting all results reported in Haugan et. al. "Consequences of Grafting Density on the Linear Viscoelastic Behavior of Graft Polymers." In Haugan et. al. we found: The linear viscoelastic behavior of poly(norbornene)-graft-poly(±-lactide) was investigated as a function of grafting density and overall molar mass. Eight sets of polymers with grafting densities ranging from 0–100% were synthesized by living ring-opening metathesis copolymerization. Within each set, the graft chain molar mass and spacing between grafts were fixed while the total backbone length was varied. Dynamic master curves reveal that these polymers display Rouse and reptation dynamics with a sharp transition in the zero-shear viscosity data demonstrating that grafting density strongly impacts the entanglement molar mass. The entanglement modulus (Ge) scales with inverse grafting density (ng) as Ge ~ ng1.2 and Ge ~ ng0 in accordance with scaling theory in the high and low grafting density limits, respectively. However, a sharp transition between these limiting behaviors occurs, which does not conform to existing theoretical models for graft polymers. A molecular interpretation based on thin flexible chains at low grafting density and thick semiflexible chains at high grafting density anticipates the sharp transition between the limiting dynamical regimes.Item Supporting data for Impact of macromonomer molar mass and feed composition on branch distributions in model graft copolymerizations(2021-12-07) Zografos, Aristotelis; Lynd, Nathaniel A; Bates, Frank S; Hillmyer, Marc A; hillmyer@umn.edu; Hillmyer, Marc A; University of Minnesota, Department of ChemistryThese files contain primary data along with associated output from instrumentation supporting all results reported in the referenced manuscript. Graft polymers are useful in a versatile range of material applications. Understanding how changes to the grafted architecture, such as the grafting density (z), the side-chain degree of polymerization (Nsc), and the backbone degree of polymerization (Nbb), affect polymer properties is critical for accurately tuning material performance. For graft-through copolymerizations, changes to Nsc and z are controlled by the macromonomer degree of polymerization (NMM) and initial fraction of the macromonomer in the feed (fMM0), respectively. We show that changes to these parameters can influence the copolymerization reactivity ratios and, in turn, impact the side-chain distribution along a graft polymer backbone. Poly((±)-lactide) macromonomers with NMM values as low as ca. 1 and as high as 72 were copolymerized with a small-molecule dimethyl ester norbornene comonomer over a range of fMM0 values (0.1 ≤ fMM0 ≤ 0.8) using ring opening metathesis polymerization (ROMP). Monomer conversion was determined using 1H nuclear magnetic resonance spectroscopy, and the data were fit using terminal and non-terminal copolymerization models. The results from this work provide essential information for manipulating Nsc and z, while maintaining synthetic control over the side-chain distribution for graft-through copolymerizations.Item Supporting data for Star-to-bottlebrush transition in extensional and shear deformation of unentangled polymer melts(2023-03-15) Zografos, Aristotelis; All, Helena A; Chang, Alice B; Hillmyer, Marc A; Bates, Frank S; bates001@umn.edu; Bates, Frank S; University of Minnesota Department Chemical Engineering and Material ScienceThese files contain primary data along with associated output from instrumentation supporting all results reported in Zografos et al. "Star-to-bottlebrush transition in extensional and shear deformation of unentangled polymer melts." A series of model poly((±)-lactide) (PLA) graft copolymers were synthesized using ring-opening metathesis polymerization and used to probe the star-to-bottlebrush transition in shear and extensional flows. Ten samples with backbone degrees of polymerization 10 < Nbb < 430, each containing one PLA side chain of length Nsc = 72 per two backbone repeat units, were investigated using small-amplitude oscillatory shear (SAOS) and extensional rheometry measurements. The star-like to bottlebrush transition was identified at Nbb = 50-70 using SAOS. In extension, melt strain hardening is absent in the star-like melts (Nbb < 50) but is prominent in the bottlebrush limit (Nbb > 70). The onset of melt strain hardening occurs at a timescale equivalent to the Rouse time of the backbone. A molecular interpretation of these results builds upon recent speculation related to strain-induced increases in interchain friction in bottlebrush polymers. These findings will be useful in designing bottlebrush melts to strain harden, which is critical in various types of processing methods involving extensional flows, including foaming, 3D printing, and film-blowing.