Orgo Lab Final: Polymers

What kind of polymerization was the formation of Nylon-10,6 ?

condensation

HCl was expelled

During Preparation of Nylon-10,6 thru Interfacial Polymerization:

Why did we use diacid chloride (sebacoyl chloride) instead of dicarboxylic acid?

because the acid halide is more reactive

What was the purpose of NaOH in the formation of nylon?

to neutralize the HCl byproduct that was formed from the polymerization

What is the byproduct of the formation of Nylon-10,6?

HCl from condensation rxn

What are the three stages of chain addition polymerization?

initiation, propagation, termination

What is the general structure of molecules that addition polymers are made from (the monomer)?

in chain addition polymerization

C to C DOUBLE BOND with four R groups coming off the Carbons

vinyl type monomer

Describe the initiation step of chain addition polymerization.

How will it occur?

an INITIATOR will form a reactive species (RADICAL)

radical formed because initiators have weak bonds that will break easily with appropriate heating

Describe the propagation step of chain addition polymerization

radicals react with VINYL monomer to begin chain addition process

active species will continue to add individual monomer units to the end until all of the monomer is used up and a polymer chain is generated

Where are functional groups found in condensation polymerizations?

functional groups are part of the polymer backbone

formed as monomer units link together

Describe the termination step of chain addition polymerization

when two individual chains react together so no new radical is made

without radical it can no longer propagate

Where are functional groups found in chain addition polymerizations?

functional groups stem from polymer chain

simple hydrocarbon backbone

How does the amount of monomer influence the MW of a polymer?

Why?

increasing amount of monomer = increasing MW

MW increases because longer chains can be made

How does the amount on initiator influence the MW of a polymer?

Why?

increasing amount of initiator = decreasing MW

MW decreases because more initiator means more chains can be made, but they will be shorter overall

Describe the bonds in the cross-linking polymerization:

between what are they formed?

describe their character.

the bonds are weak and can form and break easily

the bonds are formed between the borate ions and the OH groups in the polymer chains, this is the cross-linking

What is the general difference between polymer chemistry and other types of organic chemistry as far as the actual chemical reactions?

organic rxns: there is only ONE active site on both things that are reacting

- makes one molecule

polymer rxns: there are TWO active sites on both things reacting

- allows for formation of polymer

Give specific examples of the different processes of esterification between regular organic chemistry and polymer chemistry.

organic rxns: an alcohol and a carboxylic acid react to form an ester

polymer rxns: a diol and a diacid react to make a polymer of esters

define homopolymer

a homopolymer has the same monomer unit making up the polymer chain

define block copolymer

a block copolymer has two different monomer units that alternate and make up the polymer chain

which part of a polymer determines its properties/characteristics?

Why?

the monomer determines a polymers properties and characteristics NOT the initiator

the repeat units of the monomer, n, is very large relative to the single molecule of initiator

What was the objective of the renewable block copolymers experiment?

to determine how the physical and mechanical properties of a triblock copolymer changes as the proportions of the "soft" midblock and "hard" endblock are varied

What is a lactone?

a cyclic ester formed from hydroxy acids

In our experiment for the synthesis of a homopolymer, what was the:

monomer:

initiator:

catalyst:

product(homopolymer):

monomer: delta-decalactone

initiator: benzene dimethanol

catalyst: DPP (diphenyl phosphoric acid)

homopolymer product: poly(delta-decalactone)

Describe the characteristics of the homopolymer formed?

Why is it this way?

poly(delta-decalactone)

is viscous (thick, sticky), amorphous liquid

has these features because of the flexibility of the alkyl backbone

during polymerizations, what type of esterification do lactones undergo?

ring-opening transesterification

Which part of the formed copolymer is the midblock?

What will be the characteristics of the final polymer if there is a large proportion of this midblock?

the homopolymer - poly(delta-decalactone) is the midblock

"soft"

the properties of the copolymer will be more clear, flexible and tacky

In the synthesis of the triblock copolymer:

What is the initiator?

What is the monomer?

catalyst?

In the synthesis of the triblock copolymer:

Initiator: the homopolymer, poly(delta-decalactone)

monomer: L-lactide end block

catalyst: Sn(Oct)2

What part of the formed copolymer is the endblock?

What will be the characteristics of the final polymer if there is a large proportion of this endblock?

the poly(L-lactide) is the endblock

"hard"

the properties of the copolymer will be more tough, opaque and rigid.

What is the formula for calculating the number of monomer repeat units (n)?

mol monomer

n = ---------------------

mol initiator

What is the formula for calculating the theoretical MW of a polymer (Mn)?

Mn = MW initiator + (n X MW monomer)

what is the purpose of annealing the copolymer?

annealing melts the polymer and removes excess solvent

makes it stronger once it re-cools

purpose: TO REMOVE EXCESS SOLVENT

What is the overall equation of the cross-linked procedure we did with polymers?

PVA + borax (Na2B4O7) -------> slime

**under aqueous conditions

Which reagent is the limiting reagent in the synthesis of the homopolymer?

benzene dimethanol

What type of polymerization was the renewable triblock copolymer experiment?

chain-growth mechanism

why do polymers burn easily?

they are tightly packed, when heat is applied they will stay together in one film