Test 1 biopolymers and biocompatibility

What are the 4 free radical polymerization techniques

Bulk suspension Solution Emulsion

what polymerization technique has these advantages; Simple, no contaminants added

bulk

what polymerization technique has these disadvantages; Reaction exotherm difficult to control; high viscosity

bulk

what polymerization technique has these advantages; Heat readily dispersed; low viscosity; polymer obtained in granular form and may be used directly

suspension

what polymerization technique has these disadvantages; Washing and/or drying required; agglomeration may occur; contamination by stabilizer

suspension

what polymerization technique has these advantages; Heat readily dispersed; low viscosity; may be used directly as solution

solution

what polymerization technique has these disadvantages; Added cost of solvent; solvent difficult to remove; possible chain transfer with solvent; possible environmental pollution

solution

what polymerization technique has these advantages; heat readily dispersed; low viscosity; high molecular weight obtainable; may be used directly as emulsion; works on tacky polymers

emulsion

what polymerization technique has these disadvantages; contamination by emulsifier and other ingredients; chain transfer agents often needed to control DP; washing and drying necessary for bulk polymer

emulsion

what is required for bulk polymerization

Monomer + initiator

what is required for solvent polymerization

monomer + initiator + solvent

what is required for suspension polymerization

lots of water, monomer is an oil base

what is required for emulsion polymerization

initiator not inside droplets

how many ways are there to limit the MW in step-reaction polymerization

3

what is the first way to limit the MW in step-reaction polymerization

quench the polymerization reaction by rapid cooling when desired MW is obtained

what is the second way to limit the MW in step-reaction polymerization

Use an excess of one monomer when two difunctional monomers are polymerized

what is the third way to limit the MW in step-reaction polymerization

use small amounts of monofunctional reactant

what method of polymerization involves solutions of the two monomers in separate, immiscible solvent, one usually being water. when the two monomers are brought into contact, polymer is formed at the interface

interfacial polymerization

The ___ of any linear polymer having end groups that can be measured by ___ or ___ means can theoretically be determined if the method of measurement is sensitive enough

Mn chemical physical

End groups are present in ___ concentrations. presently avalible techniques allow a practical upper limit of molecular weight measurements of about ___

very low 50,000

1. Titration, using either indicators or potentiometric techniques

2. elemental analysis of element-specific end groups

3. measurement of activity of a radioactive-tagged end group

4. ultraviolet spectroscopic determination of an end group with a characterizable chromophore. Infrared and nuclear magnetic resonance (NMR) spectroscopic techniques are of more limited use

End group determination

end group analysis ___ be applied to branched polymers unless the ___ is known with certainty thus it is practically limited to linear polymers

cannot number of branched

in a linear polymer there are ___ as many end groups as polymer molecules

twice

if the polymer contains different groups at each end of the chain and only one characterizable end group is being measure, the number of this type is equal to the ___

number of polymer molecules

Measurement of molecular weight by end group analysis is only meaningful when the ___ and ___ are well understood

mechanism of initiation termination

Define Amorphous

a physical state characterized by almost complete lack of order among the molecules

Define crystalline

the situation where polymer molecules are oriented in a regular array analogue to a degree to crystal lattice packing in a nonpolymeric solid

what are the following- dipole-dipole, induction forces, dispersion or london or van der waals forces between nonpolar molecules, ionic bonding and ion-dipole interaction between polymers containing ionic forces

intermolecular forces of polymers

what often forms dimers in vapor phase

Carboxylic acids

the temperature below which the physical properties of amorphous materials vary in a manner similar to those of a crystalline phase, and above which amorphous materials behave like liquids

glass transition temperature

what determines the glass transition temperature?

chemical structure, methods of measurements, molecular weight

when a polymer has a ___ structure with little or no chain branching, or when it contains ___ groups that give rise to very strong dipole-dipole interactions, it may exist in crystalline form

highly stereoregular highly polar

such crystallinity is unlike that of ___ compounds but exists instead in regions of the polymer matrix where polymer molecules order themselves in a ___ favorable alignment

low molecular weight thermodynamically

crystallinity is induced in any number of ways- cooling of molten polymer, ___ solution, or heating of a polymer under vacuum or in an ___ at a specific temperature, a process called annealing.

evaporation of polymer inert atmosphere

what is the process of Drawing

crystallization may be brought about by stretching a polymer sample at a temperature above its TG

crystalline structures are generally tougher, ___, more opaque, ___, and of higher density than their amorphous counterparts.

stiffer more resistant

the higher degree of crystallinity the more ___ the properties are

pronounced

The superior mechanical properties are a reflection of the greater ___ arising from more effective ___ forces among the closely packed molecules.

cohesive strength intermolecular forces

opaqueness arises from ___ by the crystallites

scattering of light

stereoregularity is ___ a prerequisite to crystallinity

not

what is the most severe mechanism for decreasing molecular freedom

chemical crosslinking

how does chemical crosslinking work

linking the polymer chains together through covalent or ionic bonds to form a network

what kinds of physical crosslinking exist

ionic crosslinks, crystalline polymers, block polymers

what are mechanical properties dependent upon

temperature and time

what is creep

measure of the change in strain when a polymer is subjected to a constant stress

what is stress relaxation

the decrease in stress when a sample is elongated rapidly to constant strain

What is thermal stability (TGA)

primarily a function of bond energy

when ___ increases to the point where ___ causes bond rupture, the polymer degrades

temperature vibrational energy

thermal stable polymers have high ___ or ___

Tg Tm

what is a biomaterial

nonviable material used in a medical device intended to interact with biological systems

how long is an implant intended to be used

30 or more days

what is regeneration

the renewal of a tissue or organ at the completion of healing

what is repair

the formation of scar at a site at the completion of healing

what is remodeling/maintenance/ turnover

process where ECM is replaced in a process of degradation followed by synthesis

what is an autotransplant

transplant to the same patient

what is an allotransplant

donor to another person

what is a heterotransplant/xenotransplant

donor to another species

what is the property of the materials to cause no biological effect on surrounding tissues and the whole organism and in its turn to resist their influence

biological inertness

what is the property of a material to perform a definite function in the organism during the time required with no harm to the latter

biological compatibility

what is the property of a material to have strong interactions with the cells and tissues, and positively affect the cells and tissues

bioactive

if only a few monomer units are joined the resulting low MW polymer is called what

oligomer

what is a homochain

only have carbon as the backbone

what is a heterochain

having more than carbon as the backbone

what kind of polymer is this

homopolymer

what kind of polymer is this

random copolymer

what kind of polymer is this

alternating copolymer

what kind of polymer is this

block copolymer

what kind of polymer is this

graft copolymer

what polymer structure is this

linear

what polymer structure is this

branched

what polymer structure is this

network

what polymer structure is this

star

what polymer structure is this

comb

what polymer structure is this

dendrimer ladder

what polymer structure is this

ladder

what polymer structure is this

what is this process? MW increases by the successively linking of monomer molecules to the end of a growing chain

chain growth polymerization

What is this process? polymer chains are built up in a stepwise fashion by the random union of monomers to form dimers, trimers, and higher species throughout the monomer matrix

step growth polymerization

what are the two kinetic steps for chain reaction polymerization

initiation propagation

what is this step

initiation

what is this step

propagation

what is this step

termination

most step reaction polymerizations are what

condensation precesses

most chain reaction polymerizations are what

addition processes

is this a step or chain reaction? growth occurs throughout matrix by reaction between monomers, oligomers, and polymers

step

is this a step or chain reaction? DP* low to moderate

step

is this a step or chain reaction? monomer consumed rapidly while MW increases slowly

step

is this a step or chain reaction? no initiator needed; same reaction mechanism throughout

step

is this a step or chain reaction? no termination step end groups still reactive

step

is this a step or chain reaction? polymerization rate decreases steadily as functional groups consumed

step

is this a step or chain reaction? growth occurs by successive addition of monomer units to limited number of growing chains

chain

is this a step or chain reaction? DP* can be very high

chain

is this a step or chain reaction? monomer consumed relatively slowly, but MW weight increases rapidly

chain

is this a step or chain reaction? initiation and propagation mechanisms different

chain

is this a step or chain reaction? usually chain-terminating step involved

chain

is this a step or chain reaction? polymerization rate increases initially as initiator units generated; remains relatively constant until monomer depleted

chain

what polymerization classification is this? The same as step reaction polymerization with concurrent formation of low MW byproducts (pet synthesis)

polycondensation

what polymerization classification is this? the same as step reaction polymerization without byproduct formation

polyaddition

what polymerization classification is this? the same as chain reaction polymerization without formation of byproducts (PE)

chain polymerization

what polymerization classification is this? the same as chain reaction polymerization with the formation of low MM byproducts

condensative chain polymerization