Longitudinal growth of polymer crystals from flowing solutions. XI. The friction with the rotor surface

Torfs, J. C. M.; Pennings, A. J.

doi:10.1002/app.1983.070280107

Cited by 2 publications

(1 citation statement)

References 12 publications

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“…As is well known, the shish-kebab crystals tend to adhere to the stirrer during and subsequent to their formation. In the "surface growth" methodology for shish-ribbon preparation, the gel and fiber formation rates are influenced by the nature of the couette bob surface (5,7,41,(46)(47)(48). If fine particles were dispersed in the solvent during the polymer dissolution process, absorption of the macromolecules a t the particle-solvent interface might stabilize the dispersion.…”

Section: Effect Of Fine Particlesmentioning

confidence: 99%

Low density foams produced from sheared ultra‐high‐molecular‐weight polyethylene gels

Matthews¹,

Hoffman²

1990

Polymer Engineering & Sci

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Low‐density foam (0.02–0.09 g/cc) was produced from gels of ultrahigh molecular weight (UHMW) polyethylenes in solvents with melting points above ambient. The hot PE solutions were stirred at high speed to induce extended chain crystalline gels. These gels were subsequently cooled to allow the solvent to solidify and then the solvent was extracted with alcohol or sublimed. This resulted in a tough, low density foam or a collapsed mass depending mainly on the concentration of the polymer. Shrinkage was significant until polymer concentrations reached 4–5%. Foam cell size varied between 5–30 μm, or 25–75 μm depending on the method of preparation. Polarizing microscopy revealed both spherulitic and row‐nucleated structures depending on the thermal history followed during the sample preparation. We were also interested in whether or not small particles could be used to influence the nucleation and growth of the solution crystallization process. These particles could be suspended in the gel and stabilized in something like a colloidal necklace as has been proposed recently. We successfully incorporated small (0.5 μm) tungsten particles in UHMWPE gels which remained in the foam on extraction of the solvent. Polyethylene containing carbon black particles produced less successful results. These effects may be related to absorption associated with gelation of UHMWPE.

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Section: Effect Of Fine Particlesmentioning

confidence: 99%

Low density foams produced from sheared ultra‐high‐molecular‐weight polyethylene gels

Matthews¹,

Hoffman²

1990

Polymer Engineering & Sci

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Noncovalently Functionalized Block Copolymers Possessing Both Hydrogen Bonding and Metal Coordination Centers

2006

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Block copolymers containing both hydrogen bonding and metal coordination sites have been synthesized by ring-opening metathesis polymerization and subsequently functionalized using noncovalent interactions. The resulting block copolymers can be viewed as "universal polymer backbones", as a wide variety of polymers with varying functionalities can be prepared by altering the noncovalent functionalization strategy of the same polymer backbone. The effect of degree of polymerization, block copolymerization, block copolymer composition, and metal coordination on the hydrogen bonding interaction has been investigated. In general, none of these variables have a profound effect on the strength of the hydrogen bonding interactions along the polymer backbones, suggesting that the metal coordination and hydrogen bonding are orthogonal to each other in block copolymers. Finally, the effect of the noncovalent functionalization on the thermal properties of the polymers was investigated. We found that the noncovalent functionalization of all copolymers via hydrogen bonding and/ or metal coordination reduced the glass-transition temperature and the thermal stability of all copolymers.

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Longitudinal growth of polymer crystals from flowing solutions. XI. The friction with the rotor surface

Cited by 2 publications

References 12 publications

Low density foams produced from sheared ultra‐high‐molecular‐weight polyethylene gels

Low density foams produced from sheared ultra‐high‐molecular‐weight polyethylene gels

Noncovalently Functionalized Block Copolymers Possessing Both Hydrogen Bonding and Metal Coordination Centers

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