http://www.psrc.usm.edu/macrog/pmma.htm (http://www.psrc.usm.edu/macrog/pmma.htm)
poly(vinyl acetate) (http://www.psrc.usm.edu/macrog/pva.htm)
(http://www.psrc.usm.edu/macrog/pva.htm) page.Poly(methyl methacrylate), or PMMA, is a hard, tough, and shiny plastic, and if when it forms in the wet paint, it makes the paint surface, hard, tough and shiny. This is good. We want paint to do this. But there's a problem. PMMA is hydrophobic. It doesn't dissolve in water, and a lot of paints are water based.
This is where poly(vinyl alcohol-co-vinyl acetate) comes to the rescue. You see, this copolymer has an identity crisis. The alcohol groups are hydrophilic. They love water, and want to dissolve in it. But the acetate groups are hydrophobic. They hate water and don't want to dissolve in it. So when you put the copolymer in water, it forms into a ball. The alcohol repeat units are on the outside of this ball, happily embracing the water, while the acetate groups are on the inside of the ball, hiding from it.(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000497825-pva04.gif)
Now ask yourself this question.Haahaaa...I love this part :) If you were a molecule of PMMA, and as a PMMA molecule you hated water, where would you go? Would you go out into the water, or would you go into the inside of that coiled polymer, away from the water? You'd go to the inside of the coil of course! And that's just what the real PMMA does. The PMMA hides in the hydrophobic center of the coiled polymer. By doing this, it can stay suspended in water based paints! A suspension of an insoluble substance, like PMMA, held in suspension by being wrapped in another kind of molecule, like our copolymer, is what we call a latex. That's where we get the name latex paint.
Rhodium was right on the money when he coined the term "behemoth" when describing the new gaak amphoteric beasts
Two things here.
First is copolymer permeability via ammonium salts
EUDRAGIT® RL 100 and RS 100 are copolymers of acrylic and methacrylic acid esters
with a low content in quaternary ammonium groups. The ammonium groups are present as
salts and make the polymers permeable.
Second is this...thoughts to ponder!
>I don't think that starch is a major headache in precursor extraction, or is it?
What if they are including amphoteric starches as well?
AMPHOTERIC STARCH
Composition: The word "amphoteric" implies that a chemical product has both positive and negative ion groups when it is dissolved in solution. When papermakers refer to amphoteric starches they are usually referring to products derived from corn starches. The least expensive starch products are based on dent corn, a corn variety that is also the source of most corn sweetener. Amphoteric starches also are prepared from waxy maize, a variety of corn that produces only the branched type of starch, amylopectin. The cationic groups are the same quaternary ammonium substituents used in preparation of cationic starches. The anionic groups usually are phosphates. Strictly speaking all cationic potato starches are really amphoteric starches since potato starch contains about 0.08% phosphorous. The cationic content of amphoteric starches is typically in the range of 0.2 to 0.3% nitrogen. All of these products are delivered to the mill as a dry powder having a moisture content of 10 to 20%.
Function: Enhancement of dry strength. Possibly useful for improving drainage and retention, especially in systems where alum is also used.
Amphoteric Starch (http://www4.ncsu.edu/~hubbe/AMST.htm)
(http://www4.ncsu.edu/~hubbe/AMST.htm)http://www-saps.plantsci.cam.ac.uk/docs/protoplastpb.doc (http://www-saps.plantsci.cam.ac.uk/docs/protoplastpb.doc)
http://www.accessexcellence.org/AE/AEPC/WWC/1993/protoplast.html (http://www.accessexcellence.org/AE/AEPC/WWC/1993/protoplast.html)