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Effects of molecular weight of methylphenyl-containing vinylsiloxy-functionalized terpolysiloxanes on their UV-activated crosslinking by hydrosilylation at room temperature in air, shelf life stability of "all-in-one" pastes prepared from them for additive manufacturing, and mechanical properties of the resulting crosslinked elastomers, are investigated. It is found that while rheology of pastes containing base polymers, trimethylsilylated silica fillers, and thixotropic additives is not significantly affected by the base polymer molecular weight but is dominated by the filler concentration, the pastes based on higher molecular weight polymers exhibit faster crosslinking (corresponding to higher catalyst turnover numbers) and their crosslinked elastomers show transient strain-induced crystallization. The latter appears in networks from terpolymers with degrees of polymerization (DP) of 240 and above (corresponding to about one half of the critical polydimethylsiloxane chain length for entanglement formation of DP = 460), within the temperature range of -80 to -30 °C, characteristic for polydimethylsiloxane melting transition. It is believed that this is the first time an observation of this chain length effect is reported for polysiloxane elastomers and that the properties reported herein can be expected to have major implications on the application potential of these polymers in both additive manufacturing and performance of their elastomers at sub-ambient temperatures.

Algae have great potential to address a number of important needs such as water remediation and as a feedstock for biofuel and biochemicals. At present, harvesting or removing algae is expensive, especially in terms of the cost of making biofuel. The expense of harvesting algae arises from the cost of pumping and processing large amounts of water. In an effort to explore less expensive methods for harvesting, a series of weak anion exchange resins incorporating various weak bases with different pKa values were developed to bind and release algae as a function of pH. The best of these resins bind about 10% of their weight in algae, show 100% reversibility and reusability, and the ability to concentrate algae from dilute suspension to 30 g L−1. Furthermore, they have the potential for desalting algae grown in high salt media. These resins provide a low cost method for harvesting algae without pumping water or introducing large amounts of chemicals into the feedwater, harvested algae, or the environment. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1143–1149, 2013