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polymer information that makes a difference
Chemistry:
the backbone and the chemical groups attached to the backbone
carbon
comprises the backbone of most polymers, bonding to itself or to oxygen
bonding to nitrogen
less strong and stable
backbone atoms bonded to other atoms or groups:
hydrogen, polar groups, non polar groups
polar groups:
attract water, some dye, some soiling
non polar group (methyl)
do not attract water, some dyes, some soiling
degree of polymerization
the length of the polymers
more monomers =
longer chain
longer chains =
higher strength
Why longer chains and more monomers?
because more force is needed to separate longer chains
the arrangement of polymers is what?
orientation and crystallinity
oriented means: (longitudinally)
most of the polymers lie parallel to the fiber
crystalline means:
adjacent polymers are closely packed together
amorphous
less crystallinity and far apart
orientation and crystallinity are different, but they often
correlate
polymers that are highly oriented are
often highly crystalline
high orientation and high crystallinity =
higher strength and less absorbency
Forces of attraction: different kinds of bonding. How are the polymers held close to one another? Possibilites:
Hydrogen bonds, Van Der Waals forces, ionic or electrostatic bonds (aka salt bridges)
hydrogen bonds:
a strong attraction between positive hydrogen atoms in one chain, to negative oxygen or nitrogen atom of an adjacent chain
van der Waals forces:
very weak electrostatic forces between atoms
Natural fibers share common properties:
absorbent and prone to damage from insects, mold, mildew
plants are made up of…
cellulose polymers
flax and cotton are composed of
cellulose polymers
cotton fiber…
from the seed
flax fiber….
from the stem, root
cellulosic fibers share common properties
absorbent, prone to damage from insect, mold, mildew, low heat retention (heat passes through easily), low resiliency (wrinkle easily), high electrical conductivity (no static charge), flammable
