Well-dispersed and long-term stable carbon nanotubes/polyol dispersions were prepared by a mechanochemical approach with the aid of dispersing agent. Polyurethane (PU)-carbon nanotube nanocomposites were prepared by further in situ polymerization. Multi-walled carbon nanotubes (MWNT) can be dispersed individually. Fourier transform infrared (FTIR) spectra suggested that the addition of carbon nanotubes improved the degree of phase separation of polyurethane. Dynamic mechanical analysis (DMA) suggested that glass transition temperature (T g ) of polyurethane decreased with increasing carbon nanotube content slightly. Tensile test suggested that MWNT is more helpful to improve the modulus than single-walled carbon nanotube (SWNT), which is more favourable to improve the elongation of polyurethane. The different reinforcing effects of MWNT and SWNT on PU were correlated to the shearing thinning exponent and the shape factor of carbon nanotubes in polyol dispersion. Raman shift of SWNTs can reflect the dispersion state of SWNT in polyol or in PU, and the interaction between polymer and SWNT. Both SWNT and MWNT can improve the thermal stability of polyurethane and thermal conductivity.

Preparation and characterization of polyurethane-carbon nanotube composites

Aliphatic polyester block polymers constitute a highly useful and amazingly versatile class of self-assembled materials. Analogous to styrenic block polymers in both design and function, the property profiles of these degradable materials can be precisely tailored by altering the chemical structure of the components. Driven by this ideal, we have examined the impact of n-alkyl substituents on the polymerization thermodynamics and kinetics of substituted δ-valerolactone monomers and developed guiding design principles based on critical structure–property relationships in the resulting aliphatic polyesters. Under bulk room temperature conditions the polymerization rate depends strongly on substituent position and exhibits a more modest dependence on alkyl length (from −CH3 to −(CH2)8CH3). The enthalpy and entropy of polymerization are significantly influenced by substituent position, but both are largely insensitive to n-alkyl length. However, the physical properties of the resulting aliphatic polyesters de...

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Aliphatic Polyester Block Polymer Design

Carbon dioxide/epoxide copolymerization is an efficient way to add value to waste CO2 and to reduce pollution in polymer manufacturing. Using this process to make low molar mass polycarbonate polyols is a commercially relevant route to new thermosets and polyurethanes. In contrast, high molar mass polycarbonates, produced from CO2, generally under-deliver in terms of properties, and one of the most widely investigated, poly(cyclohexene carbonate), is limited by its low elongation at break and high brittleness. Here, a new catalytic polymerization process is reported that selectively and efficiently yields degradable ABA-block polymers, incorporating 6-23 wt % CO2. The polymers are synthesized using a new, highly active organometallic heterodinuclear Zn(II)/Mg(II) catalyst applied in a one-pot procedure together with biobased e-decalactone, cyclohexene oxide, and carbon dioxide to make a series of poly(cyclohexene carbonate-b-decalactone-b-cyclohexene carbonate) [PCHC-PDL-PCHC]. The process is highly selective (CO2 selectivity >99% of theoretical value), allows for high monomer conversions (>90%), and yields polymers with predictable compositions, molar mass (from 38-71 kg mol-1), and forms dihydroxyl telechelic chains. These new materials improve upon the properties of poly(cyclohexene carbonate) and, specifically, they show good thermal stability (Td,5 ∼ 280 °C), high toughness (112 MJ m-3), and very high elongation at break (>900%). Materials properties are improved by precisely controlling both the quantity and location of carbon dioxide in the polymer chain. Preliminary studies show that polymers are stable in aqueous environments at room temperature over months, but they are rapidly degraded upon gentle heating in an acidic environment (60 °C, toluene, p-toluene sulfonic acid). The process is likely generally applicable to many other lactones, lactides, anhydrides, epoxides, and heterocumulenes and sets the scene for a host of new applications for CO2-derived polymers.

Switchable Catalysis Improves the Properties of CO2-Derived Polymers: Poly(cyclohexene carbonate-b-ε-decalactone-b-cyclohexene carbonate) Adhesives, Elastomers, and Toughened Plastics.

http://pubs.acs.org/doi/pdf/10.1021/acs.biomac.5b01698

Thermodynamic Presynthetic Considerations for Ring-Opening Polymerization

Monomer design strategies to create natural product-based polymer materials

Pressure-sensitive adhesives (PSAs) are prepared with plant-based thermoplastic polyester elastomers (TPPEs), rosin ester tackifier, and epoxidized soybean oil plasticizer. Controlled bulk ring-opening transesterification polymerization of e-decalactone and l-lactide using diethylene glycol as an initiator gives ABA type block polyesters via a one-pot, two-step process with only tin(II) ethylhexanoate. Three semicrystalline poly(l-lactide)–poly(e-decalactone)–poly(l-lactide) (PLLA–PDL–PLLA) triblock copolymers are prepared containing 100 kg mol–1 PDL midblocks and 8–30 wt % PLLA end blocks with narrow dispersities. The mechanical behavior of the triblock architectures is investigated by tensile experiments. The triblocks are combined with the tackifier of 50 wt % and the plasticizer of 15–30 wt %. The thermal, viscoelastic, and morphological properties of the elastomers and the adhesive formulations are determined with differential scanning calorimetry, thermal gravimetric analysis, dynamic mechanical ana...

Preparation and Characterization of a Renewable Pressure-Sensitive Adhesive System Derived from ε-Decalactone, l-Lactide, Epoxidized Soybean Oil, and Rosin Ester

Young-Wun Kim

Papers

Preparation and Characterization of a Renewable Pressure-Sensitive Adhesive System Derived from ε-Decalactone, l-Lactide, Epoxidized Soybean Oil, and Rosin Ester

Effect of the individual and combined use of cardanol-based plasticizers and epoxidized soybean oil on the properties of PVC

Renewable malic acid-based plasticizers for both PVC and PLA polymers

Tunable softening and toughening of individualized cellulose nanofibers-polyurethane urea elastomer composites.

Thermoset elastomers derived from carvomenthide.