PDMS microspheres as rheological additives for PDMS-based DIW inks
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Engineering topics
Beach, James
Publications and source records attributed to Beach, James.
Thixotropic polysiloxane pastes for additive manufacturing
Shelf-stable, rapid crosslinking, “all-in-one” pastes useful as “inks” in additive manufacturing are provided. These pastes exhibit desirable rheological flow properties and crosslinking upon exposure to UV light. The pastes are based on vinylsilyl-functionalized, completely amorphous, linear terpolysiloxanes containing predominantly dimethylsiloxy- repeat units with small amounts of diphenylsiloxy-, methylphenylsiloxy-, diethylsiloxy-, and/or methyltrifluoroalkylsiloxy- crystallization disruptors. The base polymers are preferably compounded with a trimethylsilylated-hydrophobic silica filler, thixotropic flow agent, hydrosilyl-functionalized oligomeric crosslinker, and a catalytic system comprising platinum (II) acetylacetonate or trimethyl(methylcyclopentadienyl)-platinum (IV), and diethyl azodicarboxylate.
Messman, Jamie Michael↗
One-Component, Vinyl-Functional Fluorosilicone Pastes for Direct Ink Write Additive Manufacturing
In this study, one-component (“all-in-one”) fluorosilicone pastes specifically designed for application in direct ink write (DIW) additive manufacturing (AM) have been developed. They consist of vinyl-functional, methyltrifluoropropyl-containing (MeTfpS) terpolysiloxane base polymer(s), hydrosilyl-functional cross-linker(s), UV-sensitive hydrosilylation catalyst, thixotropic additive, and trimethylsilylated fumed silica filler, with other additives that are optional. Their base polymers were completely amorphous and linear, with molecular weights (M n ) ranging from approximately 7000 to 50,000 and specifically targeted for the viscosity range ideal for DIW. These polymers were prepared by anionic ring-opening polymerizations (A-ROP) of appropriate mixtures of cyclic siloxanes initiated by oligomeric, difunctional tetramethylammonium silanolate in the presence of a difunctional tetramethyldivinyldisiloxane end-blocker and molecular weight regulator. Two series of these terpolymers were prepared: one containing 5 mol % MeTfpS repeat units but varying degrees of polymerization (DP) from 80 to 600 and the other containing 5, 10, and 15 mol % MeTfpS at a constant DP of 600. All polymers contained mostly random distributions of MeTfpS repeat units. The pastes were prepared by speed-mixing, ready for use in DIW, they exhibited ideal thixotropy, long-term (over a year) rheological stability, and can be quickly (within seconds) and permanently cured by room-temperature, UV-activated hydrosilylation in air. The resulting elastomers showed base polymer molecular weight- and composition-dependent stress-induced crystallization (SIC) at higher molecular weights and lower trifluoropropyl contents and tunable Shore A hardness (30A–40A) typical for soft polysiloxane rubbers. Preliminary DIW tests indicated excellent printability with high precision of printed shapes and clearly present these one-component pastes as prime candidates for simple and practical printing of silicone elastomer objects.
36 MATERIALS SCIENCE↗
Thixotropic polysiloxane pastes for additive manufacturing
Shelf-stable, rapid crosslinking, “all-in-one” pastes useful as “inks” in additive manufacturing are provided. These pastes exhibit desirable rheological flow properties and crosslinking upon exposure to UV light. The pastes are based on vinylsilyl-functionalized, completely amorphous, linear terpolysiloxanes containing predominantly dimethylsiloxy-repeat units with small amounts of diphenylsiloxy-, methylphenylsiloxy-, diethylsiloxy-, and/or methyltrifluoroalkylsiloxy-crystallization disruptors. The base polymers are preferably compounded with a trimethylsilylated-hydrophobic silica filler, thixotropic flow agent, hydrosilyl-functionalized oligomeric crosslinker, and a catalytic system comprising platinum(II) acetylacetonate or trimethyl(methylcyclopentadienyl)-platinum(IV), and diethyl azodicarboxylate.
Messman, Jamie Michael↗
Comparative Aging Assessment of Polysiloxane Materials
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Weber, Holly↗
Thixotropic polysiloxane pastes for additive manufacturing
Shelf-stable, rapid crosslinking, “all-in-one” pastes useful as “inks” in additive manufacturing are provided. These pastes exhibit desirable rheological flow properties and crosslinking upon exposure to UV light. The pastes are based on vinylsilyl-functionalized, completely amorphous, linear terpolysiloxanes containing predominantly dimethylsiloxy-repeat units with small amounts of diphenylsiloxy-, methylphenylsiloxy-, diethylsiloxy-, and/or methyltrifluoroalkylsiloxy-crystallization disruptors. The base polymers are preferably compounded with a trimethylsilylated-hydrophobic silica filler, thixotropic flow agent, hydrosilyl-functionalized oligomeric crosslinker, and a catalytic system comprising platinum(II) acetylacetonate or trimethyl(methylcyclopentadienyl)-platinum(IV), and diethyl azodicarboxylate.
Messman, Jamie Michael↗