Innovations

Plastic microbeads, typically composed of non-degradable synthetic polymers like polyethylene and polypropylene, are used as exfoliants and rheological modifiers in personal care and cosmetic products (PCCPs) to improve viscosity, bulking, film formation, and abrasion. These microbeads significantly contribute to microplastic pollution as they cannot be readily collected for recycling as they directly enter the water waste stream upon use. Limited sustainable alternatives to plastic microbeads with the desired properties relevant to the PCCP industry currently exist.

Researchers at the University of Minnesota have developed new biodegradable microbeads from cheap and abundant waste biomass. The microbeads are prepared from a mixture of cellulose and Kraft lignin in a surfactant-free batch emulsion method. These microbeads meet the standards of shape, size, and stiffness required to be of interest as exfoliants and rheological modifiers in personal care products and contain no common allergens. Biocompatible and biodegradable microbeads sourced from biomass provide a sustainable alternative to plastic microbeads sourced from synthetic polymers.

Inventors: Michelle Calabrese 

Polyethylene terephthalate (PET) and common polyolefins (POs), specifically polyethylene (PE) and polypropylene (PP), represent approximately 80% of plastic waste in the US. However, recycling rates for these materials are low due to challenges in separating mixed waste streams into pure recycle material streams and the inability to mix different polymer materials together to provide a functional plastic. Researchers at the University of Minnesota have developed hydroxy-terminated POs as reactive additives for compatibilizing commercial PET/PO binary blends. Weight percentages as low as 0.5% of these reactive additives yield functional plastic blends with increased fracture strength and toughness compared to blends without the additive. Additionally, these reactive additives do not require specialized manufacturing processes nor do they release volatile components. They have been shown to enhance melt-mixes of PET/POs blends using common plastic melt-mixing technologies such as extrusion.

Inventors: Chris Ellison, Marc Hillmyer

Continuous manufacturing of solid profiled polymer parts is challenging because common polymers have strong adhesion to various surfaces such as metal, glass, and other polymers. This leads to increased friction and eventually failure of the manufacturing process. Current available techniques to manufacture high-aspect profiled polymer parts are severely limited, and often require high melting temperatures, high-pressures, and complex machinery. Newly developed 3D printing techniques such stereolithography or vat photopolymerization can convert a liquid resin into solid parts via photopolymerization. However, they have limited applicability due to their finite build volumes and relatively low throughput. To address this limitation, Researchers at the University of Minnesota have developed a self-lubricated photopolymerization method that is able to continuously convert monomer fluid into a solid part. This novel method can be used to manufacture crosslinked polymer parts from various starting materials such as various meth(acrylate) monomers, but could also be readily extended to other photopolymerizable monomers. For instance, this novel photopolymerization technique can be used to produce growing robots with enhanced capabilities.

Growing robots are inspired by the biological tip growing process through which plant roots and vines are able to direct growth to reach new locations. As such, these robots interact with the environment by growing at their tip, instead of moving through surface contact like traditional robots. Unfortunately, current robots mostly grow using solid-state materials, which severely limits lengthening and their navigation capabilities. The novel self-lubricating photopolymerization technique addresses these problems by eliminating internal friction, which in turn allows for unrestricted growth of the robot’s body through the environment. In addition, photopolymerization enables control over the material properties and growth patterns at the tip, which ultimately facilitates bending of its parts, navigation, and steering to avoid obstacles. Therefore, a growing robot utilizing the proposed method is capable of lengthening many times its original body length, burrowing in a simulated soil, passively avoiding obstacles, and traversing tortuous paths. A greater range of functionalities, including biodegradability, improved mechanical properties, and active steering, could be achieved by employing different chemistries and robot designs.

Inventors: Chris Ellison

Lignocellulosic biomass is one of the most promising renewable feedstocks for sustainable polymers due to its worldwide abundance and availability. In particular levoglucosan, the main product of cellulose pyrolysis, is especially promising because it allows for modifications pre and post polymerization. However, currently available levoglucosan functionalization and polymerization routes are severely limited. Critical drawbacks include hazardous and rigorous chemical reactions, utilization of toxic catalysts, and lacking characterization of the resulting polymers.

To address this gap, Researchers at the University of Minnesota have developed a synthetic platform to easily and safely produce levoglucosan-based polymers with different functional groups.This technology enables synthesis of tailored polymers via an optimized cationic ring-opening polymerization (cROP). Post-polymerization modifications of levoglucosan-based polysaccharides is readily performed via UV-initiated thiol–ene click reactions. Additionally, this novel platform uses biocompatible, commercially available, and recyclable catalysts, which are added at low loadings (approximately 0.5mol%). Two novel levoglucosan polymers with lauryl mercaptan and thioglycerol pendant groups have been produced and characterized as a proof of concept. This novel platform can potentially be scaled up to produce large quantities of sustainable & tailored polymers from the abundant renewable feedstock levoglucosan.

Inventors: Theresa Reineke, Chris Ellison

A new method for synthesizing skewed molecular weight polyolefins has been invented, with improved rheological behavior and processability while maintaining desired mechanical properties. By regulating the polymerization initiator addition rate and time, polymer molecular weight distributions are skewed to lower or higher molecular weights. Polymers skewed to higher molecular weights demonstrate lower viscosity than those that are skewed to lower molecular weights. Despite differences in viscosities, their mechanical performance remains the same, regardless of the skew of the molecular weight distribution. Furthermore, a broadening of molecular weight distributions enhances the shear thinning behavior of the polymer, making it more suitable for industrial melt processing techniques.

Inventors: Geoffrey Coates, Brett Fors

A new strategy has been discovered to incorporate salicylic acid moieties into commercial polymers, including PLA, polycaprolactone (PCL) and a derivative of poly(ethylene terephthalate) (PETg), through a straightforward transesterification approach. Incorporation of salicylic acid moieties has been shown to greatly enhance the hydrolytic degradability of polymers without sacrificing other material properties. Additionally, transesterification has been broadly used in polymer chemistry and can be readily incorporated into industrial processes. This new approach enables development of sustainable and degradable polymers in a simple, scalable, and cost-efficient method.

Inventors: Marc Hillmyer, Christopher Ellison

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Cellulose nanofibers are a class of nanocellulose that are favored in materials applications because of their desirable chemical, mechanical, and environmental properties. However, the isolation of these materials from biomass remains a challenge because of toxic chemicals and high-energy specialized machines required. The inventors have developed a new process to isolate cellulose nanofibers from the well characterized grass biomass source miscanthus X. Giganteas. The process uses cheap, non-toxic chemicals, does not require any mechanical treatment, and produces materials with enhanced properties.

Inventor: Stuart Rowan

Applying green chemistry principles, researchers at the University of Minnesota have developed a simple, novel method for the preparation of hydrogels composed of lactose containing polymers. This method involves an environmentally friendly, atom-economical reaction conducted in water to synthesize lactose-based methacrylic monomers, and methacrylic acid as a byproduct. This method allows for synthesis of the hydrogel through a simple pH adjustment of the reaction mixture followed by photopolymerization. In addition to the light-induced polymerization, the entire process is carried out in a single pot, making this process highly energy efficient, enabling synthesis at ambient temperature, and polymerization at high rates. The researchers have demonstrated that the water uptake, rheological and other physical properties can be tuned easily by varying the ratio of methacrylic anhydride to lactose. In addition, the process was shown to produce hydrogel with comparable properties with milk permeate (as received from a cheese processing plant) in place of reagent-grade lactose.

Inventor: Marc Hillmyer

This technology is a new multiblock copolymer compatibilizer that improves the recyclability of mixed plastic waste streams such as PET-PE (poly(ethylene terephthalate) – polyethylene). New methods are used to synthesize novel PET-PE multiblock copolymers that exhibit compatibility and mechanical strength in polyester/polyolefin multilayer films and blends. The method couples oligomers of poly(ethylene terephthalate) (PET) and polyethylene (PE). The materials enable recyclabilty of PET/PE products as blends. In addition, the new multiblock copolymer can be used as a tie-layer adhesive between polyolefin and polyester layers of a multilayer film.

Inventor: Christopher Ellison, Kevin Miller

Researchers at the University of Minnesota have developed a new method to prepare novel PSA materials from renewable resources with high bio-based contents (>90%). Specifically, a series of ABA triblock copolymers were designed and successfully synthesized with corn-derived poly(lactide) (PLA) as the glassy end blocks and poly(pentadecyl caprolactone) (PPDCL) containing a long alkyl (C15) substituent as the rubbery B-central block. This PPDCL is a new aliphatic polyester that was synthesized from cashewnut-shell-liquid-derived lactones in a controlled and tunable fashion. The new PSA material exhibits adhesion properties competitive with commercial adhesives (such as duct tape) with the added benefit of renewable bio-based contents and hydrolytic degradability.

Inventors: Christopher Ellison, Marc Hillmyer

A cost effective, new two-stage chemical process manufactures methyl-ε-caprolactone (MCL) from cresol, a fossil or bio-renewable feedstock. Details for designing a process optimized for net present value (including unit operation design of two reactors, distillation and integrated heat transfer) were determined via process simulation. The two-reaction process first hydrogenates cresol to methyl-cyclohexanone, which is then followed by Baeyer-Villiger oxidation to MCL. Improvements in overall selectivity via catalytic performance of the Baeyer-Villiger oxidation catalyst boost the overall economics of the process, rendering it a low-cost process broadly applicable to multiple classes of alkyl-phenol feedstocks. The novel process can manufacture MCL for use in polymer/plastics.

Inventors: Paul Dauenhauer, Marc Hillmyer

A new, sustainable method synthesizes acrylic acid and acrylate esters starting from alkyl lactates. The method reacts alkyl lactate with carbon monoxide and ethylene in presence of a palladium catalyst, resulting in catalytic hydroesterification of the alkyl lactates yields alkyl 2-(propionyloxy)propanoates. Pyrolysis of the alkyl 2-(propionyloxy)propanoates yields acrylate esters and propionic acid, and further hydrolysis of the acrylate esters yields acrylic acid. The synthetic method provides quantitative yields of the 2-(propionyloxy)propanoates, making it ideal for scale-up use in industry, and the catalytic species can be generated in situ in both in the neat alkyl lactate and in organic solvent from inexpensive and readily available starting materials.

Inventor: Marc Hillmyer, Ian Tonks

Polyethylene (PE) and isotactic polypropylene (iPP) are the most abundantly produced worldwide commodity plastics, representing over 120 million metric tons of the plastic produced annually. They are inexpensive monomers but represent a challenge to recycle because of their inherent immiscibility with each other, which induces substantial sorting costs. In fact, PE and iPP have poor bonding properties due to their hydrophobic composition and can only be adhered together with energy intensive and/or expensive surface functionalization or by using PE and iPP that are produced by homogenous catalysts.

Inventor: Geoffrey Coates, Anne LaPointe, James Eagan

A new process synthesizes multifunctional alcohols from bio-derived carboxylic acids. Starting with itaconic acid or mesoconic acid, this high-yield, two-step process uses heterogeneous catalysts in aqueous media as an efficient method of producing of lactones, diols and triols, where resulting alcohols such as 2-methyl butanediol and 3-methyl-1,5-pentanediol can be used to prepare polyesters. The diol compounds are created by reacting itaconic acid or mesoconic acid with hydrogen (H2) gas to form a lactone  such as (alpha/beta)-methyl-gamma-butyrolactone (MGBL).  MGBL can then be reacted further with hydrogen to make 2-methyl butane diol.  MGBL also presents an interesting possibility as a renewable, green solvent.

Inventor: Kechun Zhang, Paul Dauenhauer

A new isosorbide derivative has been synthesized which can be polymerized and incorporated into block polymers. The monomer, AMI (acetylated methacrylic isosorbide), can be efficiently synthesized in two steps from commercially available starting materials. It can be polymerized using a variety of methods including traditional free radical and Reversible Addition-Fragmentation chain Transfer (RAFT) polymerizations. The resulting polymers are isosorbide-based polymethacrylates. Additional research focusing on thermoplastic elastomer applications is on-going.

Inventor: Theresa Reineke, Marc Hillmyer

An environmentally friendly process has been developed for the synthesis of isoprenecarboxylic esters and their corresponding polymers from a fermentation product of glucose: mevalonolactone. In this method, bio-renewable mevalonate is used to synthesize mevalonolactone, which can then be converted to anhydromevalonolactone. An eliminative opening of anhydromevalonolactone using a base like tert-butoxide creates the precursor to isoprenecarboxylic esters (e.g., methyl, ethyl, n-butyl, and t-butyl derivatives) with different sizes of the ester alkyl moiety. The final step is radical polymerization of these esters or the precursor acid, using AIBN as initiator, which leads to the ultimate poly(isoprenecarboxylate) product. The varying alkyl ester moiety changes the polymer’s properties creating the possibility of polymers suited for a variety of applications.

Inventor: Thomas Hoye, Nicolas Ball-Jones, Grant Fahnhorst

A new reaction path has been discovered to make metastable lactone acid in high yield (94%) by simple mixing of a 1:1 blend of corn-based chemicals – itaconic anhydride and furfuryl alcohol – at room temperature.  In addition, multiple reaction pathways have also been demonstrated for conversion of itaconic anhydride and furans into derivatives amenable to novel polymer or chemical compound synthesis. See Image Gallery for sample of possible synthesis pathways.

Inventor: Thomas Hoye

Biobased and chemically recyclable polyurethane (PU) offers a greener alternative to petroleum derived polyols used in the synthesis of thermoplastic polyurethanes, flexible foams and elastomers. A new technique uses renewable and degradable β-methyl-δ-valerolactone (MVL), to create a bio-based PMVL (poly β-methyl-δ-valerolactone) polyol with similar mechanical properties and performance of petroleum-derived PU.

Inventor: Marc Hillmyer, Frank Bates, Christopher Macosko

A process has been developed for synthesizing two new dimethacrylate monomers from glucose and mannose. The materials produced by the sugar-derived dilactones undergo degradation in basic conditions while remaining stable in neutral and acidic environments. The dimethacrylates are derived from sugars, making them renewable and comparable to petroleum-based sources. The monomers reported are sugar-derived dimethacrylates, and provide a pathway to create sustainable materials for use in coatings, thermosets, adhesives and particle-based drug delivery.

Inventor: Marc Hillmyer, Theresa Reineke

A novel method synthesizes low-cost, polymeric valerolactones with tunable mechanical properties and low glass transition temperatures. Chemically crosslinked poly(β-methyl-δ-valerolactone) (PMVL) elastomers are created from high molar mass PMVL homopolymers that can be chemically converted back to recover the monomer in high purity. In addition, the crosslinked PMVL materials are highly tunable and exhibit lower glass transition temperature values (near −50°C).

Inventor: Marc Hillmyer

A new process uses a novel catalyst to synthesize isoprene in high yields. Isoprene is made by contacting 3-methyltetrahydrofuran (MTHF) with a heterogeneous acid catalyst (other than alumina, or Al2O3). This catalytic process dehydrates MTHF to isoprene via several combinations of temperatures, pressures, and space velocities (reactant volumetric flow rate per volume of catalyst) and achieves conversion rates of MTHF to isoprene of up to 100%.

Inventors: Paul Dauenhauer, Kechun Zhang

A method of creating a scalable block copolymer from a new branched lactone monomer has been developed. The new lactone monomer is generated from direct fermentation of sugar.  The biobased monomer, when copolymerized with lactide, has many utilities and its mechanical properties (e.g. stretchiness, strength) can be tuned depending on the application requirements. Sugar (glucose) is one of nature’s simplest and most common organic compounds, and the resultant polymers from this new process are biodegradable, affordable, and available for mass-production. Applications of these polymers are disposable materials, thermoplastics, and sustainable plastic components.

Inventors: Frank Bates, Marc Hillmyer, Kechun Zhang

A catalytic process allows commodity olefins to be synthesized from the carboxylic acids of biomass. This bio-based feedstock approach is a desirable method for generating olefins that can be used to make plastics and other chemicals. The process, which involves the decarbonylation of carboxylic acids from biomass, creates olefins such as styrene, acrylates, acrylonitrile and octene in moderate to good yield. Furthermore, by adding a tandem Heck-type coupling reaction, the process can also generate stilbenes, which are desired bioactive targets.

Inventors: Marc Hillmyer, William Tolman

To reduce the costs of making valuable C4-C5 renewable chemicals, a biosynthetic pathway has been developed to generate C4-C5 chemicals, such as succinate, amino acids and 1,4-butanediol. This new pathway from sugars involves only five fermentation steps, as compared to the current pathway, which requires 23 steps. The new process uses engineered microbes and a simple pathway that produces less contaminating byproducts and higher yields (50% higher theoretical yield). This new approach makes the production of cost-effective renewable bioplastics, polyesters and spandex a possibility.

Inventor: Kechun Zhang

This invention describes a new aliphatic polyester stereocomplex formed from the mixture of racemic, isotactic, regioregular chains of poly(propylene succinate). The resulting material has a characteristic melting point approaching that of low density polyethylene.

Inventors: Geoffrey Coates

The invention provides alternative broad-spectrum sorbents for water
purification and other applications with superior adsorption kinetics.

Inventor: William Dichtel

“CycloPure has developed the first ever porous cycodextrin polymers with selective adsorption against unwanted compounds. We rapidly remove selective pollutants present in low concentration, sustainably and cost-effectively. CycloPure provides pioneering adsorption technologies to protect human health and the environment. ” — CycloPure

Founder: William Dichtel

“Intermix Performance Materials’ multi-block compatibilizer additive technology increases the efficient and cost effective recycling of post-consumer mixed plastic waste and produces higher quality resultant resins.  The technology allows the development of superior performance polymer alloys comprised of polypropylene and polyethylene. ” — Intermix Performance Materials

Cofounders: Geoffrey Coates, Ting-Wei Lin, Andrew Arriz

“Låkril Technologies catalyzes sustainability in chemical processes through sales of acrylics and licensing of related catalyst and process technology. We provide competitive alternatives to high volume petrochemicals to help decrease the world’s CO2 intensity.  Our revolutionary catalyst technology for catalytic dehydration of α-hydroxy acids allows the supply of sustainable, bio-based acrylic acid and acrylate derivatives as drop-in replacements to the paints, coatings, adhesives, and superabsorbents industries at cost parity.” – Låkril Technologies

Founder: Paul Dauenhauer, Christopher Nicholas

Låkril Technologies Website

“LoopCO2’s research will be the development of thermoplastic elastomers that can be depolymerized back to their original monomer and reused via a recycling mechanism. Our technology will use the CO2 from the atmosphere and continuously turn them into valuable product we can use to replace the existing fossil-based plastics.” – LoopCO2

Founder: Ian Tonks

LoopCO2 Website

“Valerian Materials will lead the way in renewable, degradable, and recyclable polymers. The biomass derived materials have applications as resilient foams and elastomers as well as tough plastics and thermosets. The principal technology relies on efficient and economical fermentation of sugar to give small molecules that can be catalytically converted to polymers in high yields at low temperatures with controlled molar mass. The versatility of the polymer platform is a key aspect and allows for broad penetration in a wide variety of industries. ” — Valerian Materials

Cofounders: Kechun Zhang, Frank Bates, Marc Hillmyer