Page 643 - Carrahers_Polymer_Chemistry,_Eighth_Edition

606 Carraher’s Polymer Chemistry

TABLE 18.9
General Composition of Typical “Scotch” Tapes (By Weight)
Paint masking tape
Paper backing 55%–74%
Natural rubber adhesive 26%–45%
Transparent tape
Acrylic adhesive about 36%
Polypropylene film (backing) about 64%

Post-it notes
Acrylic adhesive < 0.5%
Inks and dyes < 0.1%
Paper > 99.5%
Vinyl electrical tape
Poly(vinyl chloride) backing 48%–54%
Polyester adipate backing 21%–27%
Hydrotreated light naphthal 4%–8%
Epoxidized soybean oil 2%–4%

Antimony trioxide (Sb 2 O 3 ) flame control 2%–4%
Piperylene-2-methyl-2-butene polymer 2%–4%
Branched alkyl phthalate plasticizer 2%–4%
Fillers and processing aids 2%–4%

It polymerizes rapidly, generally within a minute or so continuing to harden for about 24 h.
Acetone, from many finger nail polishes, can be used to soften super glue.

Super glue is based on cyanoacrylates, generally methyl-2-cyanoacrylate, ethyl-2-cyanoacrylate
(sold under trade names such as Super Glue and Krazy Glue), n-butyl cyanoacrylate (used in vet-
erinary glues such as Vetbond and LiquiVet and skin glues such as Indermil and Histoacryl), and
octyl-2-cyanoacrylate (used as a medical glue with trade names such as LiquiBand, FloraSeal,
Dermabond, SurgiSeal, and Nexaband). Cyanoacrylate glue has a low shearing strength that allows
its use as a temporary adhesive where it is employed to hold an object in place and then sheared off
later. It is used to assemble prototype electronics and to hold nuts and bolts in place and in build-
ing model aircraft. It is used as a forensic tool to capture fingerprints on glass and metals. The glue

was first used in 1966 as a spray to retard bleeding in wounded soldiers on the battlefi eld until they

could be properly cared for in a hospital. It has been used to stop cuts in professional fighters and to

repair bones in animals. Most glues are a mixture of the cyanoacrylate but with about 10% of other
material such as PMMA, hydroquinone, and small amounts of organic sulfonic acid.
Cyanoacrylates are acrylic resins that polymerize rapidly in the presence of water via attack of a
nucleophile such as the hydroxide ion. This is shown below for methyl-2-cyanoacrylate.

O
O CH
CH 3 3 CH 3
O
O O
– HO R
HO
HC
2
O C – R
N N
N
(18.4)

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