The commercial PETs used were provided by Eastman Chemicals and Arena Recycling VOF, the Netherlands; Eastman PET is a rapidly
crystallizing injection molding grade PET, and RECO PET (obtained from Arena Recycling) is a slowly
crystallizing PET recycled from soft drink bottles.
Another consideration is the exothermic reaction that may occur in the
crystallizing vessel.
Starlinger recently installed a new recycling system for PET nonwovens, consisting of a single-shaft shredder, RecoStar Basic single-screw extruder with two vacuum vents, a double-piston continuous backflush screenchanger, underwater pelletizer,
crystallizing dryer, and solid-stating unit.
The alloying and molding process developed by Remaplan started with a
crystallizing dryer, followed by an Erema Vacurema unit and then an extruder.
Erema combines predrying and
crystallizing with a proprietary "vacuum reactor" or densifier.
These include gas-fired crystallizer/dryers that save energy, two-stage drying and
crystallizing systems that extend the life of dryer components, and an on-line rheometer that monitors product intrinsic viscosity (I.V.) during pelletizing.
Crystallizing chemical compounds serves as a simple rite of passage for chemistry students.
At last month's HIV structure conference, he announced that the group had succeeded in
crystallizing p24.
Because
crystallizing this colorless, tasteless and odorless protein excludes nicotine and other potentially toxic "antinutrients," tobacco's fraction-1 protein could offer a safe food additive or pharmaceutical-grade (ultrapure) nutrient, he says.
Compound 46 begins
crystallizing at the top of the container, where hundreds of 2- to 3-millimeter needle crystals form a semipermeable meshwork.
By
crystallizing the molecule and studying it with X-ray diffraction techniques, "we now know where they [the subunits] are and how they're related to each other,' Schiffer says.
