Marc A. Hillmyer

Bio: Marc A. Hillmyer is an academic researcher from University of Minnesota. The author has contributed to research in topics: Polymerization & Copolymer. The author has an hindex of 103, co-authored 574 publications receiving 36643 citations. Previous affiliations of Marc A. Hillmyer include University of Colorado Boulder & University of North Carolina at Chapel Hill.

Synthesis and Characterization of Model Polyalkane−Poly(ethylene oxide) Block Copolymers

Abstract: We describe the preparation of a new set of amphiphilic block copolymers with well-defined molecular weights and block volume fractions. The synthesis of a variety of polyalkane−poly(ethylene oxide) block copolymers was accomplished by a new polymerization−hydrogenation sequence. Initially, anionic polymerization of either butadiene or isoprene was performed followed by end capping with ethylene oxide. The resulting hydroxyl-terminated polydienes were catalytically hydrogenated to give the corresponding hydroxyl-terminated polyalkanes. These polymeric alcohols were then titrated with potassium naphthalenide to yield the analogous potassium alkoxides. This type of macroinitiator was employed in the polymerization of ethylene oxide. Seventeen polyalkane−poly(ethylene oxide) block copolymers were prepared in near quantitative yields with molecular weights ranging from (1.4 to 8.7) × 103 and poly(ethylene oxide) volume fractions ranging from 0.29 to 0.73. These polymers are model materials for block copolymer...

Approaches to Sustainable and Continually Recyclable Cross-Linked Polymers

Abstract: Cross-linked polymers are ubiquitous in daily life, finding applications as tires, insulation, adhesives, automotive parts, and countless other products. The covalent cross-links in these materials render them mechanically robust, chemically resistant, and thermally stable, but they also prevent recycling of these materials into similar-value goods. Furthermore, cross-linked polymers are typically produced from petroleum-based feedstocks, and their hydrocarbon backbones render them nondegradable, making them unsustainable in the long term. In recent years, much effort has focused on the development of recycling strategies for cross-linked polymeric materials. In the following Perspective, we discuss many of these approaches, and highlight efforts to sustainably produce recyclable cross-linked polymers. We present our thoughts on future challenges that must be overcome to enable widespread, viable, and more sustainable and practical implementation of these materials, including the sustainable sourcing of f...

Polymeric bicontinuous microemulsions

Abstract: High molecular weight block copolymers can be viewed as macromolecular surfactants when blended with thermodynamically incompatible homopolymers. This Letter describes the formation of polymeric bicontinuous microemulsions in mixtures containing a model diblock copolymer and two homopolymers. Although we attribute development of this equilibrium morphology to the effects of fluctuations, mean-field theory provides a quantitative strategy for preparing the bicontinuous state at blend compositions near an isotropic Lifshitz point.

Mechanistic comparison of cyclic ester polymerizations by novel iron(III)-alkoxide complexes: Single vs multiple site catalysis

Abstract: The complexes Fe2(OCHPh2)6 and L2FeOR (R = Et or CHPh2, L = N,N‘-bis(trimethylsilyl)benzamidinate) were structurally characterized, and comparative studies of the behavior of those compounds comprising the same alkoxide (Ph2HCO-) in polymerizations of e-caprolactone (CL) and d,l-lactide (LA) were performed. Both Fe2(OCHPh2)6 and L2FeOCHPh2 are effective polymerization catalysts, as reflected by molecular weight control, polydispersities, and end group analysis, but the diiron complex generally exhibits greater polymerization control, particularly for CL. Kinetic investigations of the polymerization of CL revealed the same first-order dependence on [CL] for both catalysts, but different orders in [catalyst] that signified a distinct contrast in mechanism. Analysis that invoked the presence of a termination-causing impurity at low concentration yielded a first-order dependence on [Fe2(OCHPh2)6], but the order in [L2FeOCHPh2] was found to be one-half. This fractional dependence was interpreted by using a mod...

Triblock copolymer syntheses of mesoporous silica with periodic 50 to 300 angstrom pores

Abstract: Use of amphiphilic triblock copolymers to direct the organization of polymerizing silica species has resulted in the preparation of well-ordered hexagonal mesoporous silica structures (SBA-15) with uniform pore sizes up to approximately 300 angstroms. The SBA-15 materials are synthesized in acidic media to produce highly ordered, two-dimensional hexagonal (space group p6mm) silica-block copolymer mesophases. Calcination at 500°C gives porous structures with unusually large interlattice d spacings of 74.5 to 320 angstroms between the (100) planes, pore sizes from 46 to 300 angstroms, pore volume fractions up to 0.85, and silica wall thicknesses of 31 to 64 angstroms. SBA-15 can be readily prepared over a wide range of uniform pore sizes and pore wall thicknesses at low temperature (35° to 80°C), using a variety of poly(alkylene oxide) triblock copolymers and by the addition of cosolvent organic molecules. The block copolymer species can be recovered for reuse by solvent extraction with ethanol or removed by heating at 140°C for 3 hours, in both cases, yielding a product that is thermally stable in boiling water.

Science and technology for water purification in the coming decades

Abstract: One of the most pervasive problems afflicting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades, with water scarcity occurring globally, even in regions currently considered water-rich. Addressing these problems calls out for a tremendous amount of research to be conducted to identify robust new methods of purifying water at lower cost and with less energy, while at the same time minimizing the use of chemicals and impact on the environment. Here we highlight some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re-use of wastewater and efficient desalination of sea and brackish water.

Nonionic Triblock and Star Diblock Copolymer and Oligomeric Surfactant Syntheses of Highly Ordered, Hydrothermally Stable, Mesoporous Silica Structures

Abstract: A family of highly ordered mesoporous (20−300 A) silica structures have been synthesized by the use of commercially available nonionic alkyl poly(ethylene oxide) (PEO) oligomeric surfactants and poly(alkylene oxide) block copolymers in acid media. Periodic arrangements of mescoscopically ordered pores with cubic Im3m, cubic Pm3m (or others), 3-d hexagonal (P63/mmc), 2-d hexagonal (p6mm), and lamellar (Lα) symmetries have been prepared. Under acidic conditions at room temperature, the nonionic oligomeric surfactants frequently form cubic or 3-d hexagonal mesoporous silica structures, while the nonionic triblock copolymers tend to form hexagonal (p6mm) mesoporous silica structures. A cubic mesoporous silica structure (SBA-11) with Pm3m diffraction symmetry has been synthesized in the presence of C16H33(OCH2CH2)10OH (C16EO10) surfactant species, while a 3-d hexagonal (P63/mmc) mesoporous silica structure (SBA-12) results when C18EO10 is used. Surfactants with short EO segments tend to form lamellar mesost...

Chemical Routes for the Transformation of Biomass into Chemicals

Abstract: 3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481