17 Antiplasticizers for Bisphenol W.
J . J A C K S O N , JR., a n d
J.
Polycarbonates
R. C A L D W E L L
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Tennessee Eastman Co., Division of Eastman Kodak Co., Kingsport, Tenn.
S e v e r a l classes o f c o m p o u n d s a r e cizers
for
antiplasti-
bisphenol polycarbonates—that
w h e n present in
is,
concentrations up to
t h e y increase t h e tensile modulus a n d
30%, tensile
s t r e n g t h o f films a n d d e c r e a s e t h e e l o n g a t i o n . Classes o f p a r t i c u l a r l y e f f e c t i v e
antiplasticizers
a r e (1) c h l o r i n a t e d b i p h e n y l s a n d
terphenyls,
(2)
abietic
p o l y ( s t y r e n e g l y c o l s ) , a n d (3)
acid
derivatives. By incorporating these materials in
films
of
the
polycarbonates
studied,
the
t e n s i l e m o d u l i were i n c r e a s e d b y 3 0 t o a l m o s t 60%
of the intial values.
a series of polycyclic bisphenol polycarbonates was recently developed in these laboratories (5).
Because of the bulky, three-dimensional, polycyclic groups
attached to the main molecular chains, these polymers have very high glass transition temperatures—200° to 290°C.
Compared to other types of bisphenol poly-
carbonates, the polymers also have relatively low elongations—usually 3 to
30%.
T o extend the usefulness of these polymers, an effort was made to increase their flexibility
and toughness by plasticization.
M a n y compounds were tested
as
potential plasticizers, but none was found to be effective when present in concentrations of 20 to 30%.
Instead, several classes of compounds were discovered which,
in effect, acted as antiplasticizers—that is, when present in concentrations up to
30%
they increased the tensile modulus and tensile strength of films and decreased the elongation.
Also, the glass transition temperatures of the polymers were depressed
appreciably less by these antiplasticizers than by conventional plasticizers.
Since
the authors were also interested in films which were suitable for applications requiring a relatively high tensile modulus (such as in photographic film and magnetic tape), the action of the antiplasticizers was studied.
Results reported here were
obtained with three classes of commercially available compounds which were particularly effective
antiplasticizers for these polycarbonates: (1)
biphenyls and terphenyls; (2) poly (styrene glycols), formula A ; and (3)
chlorinated derivatives
of abieticacid, formulai*. M o s t of the experiments were carried out with two model polycarbonates 185
Platzer; Plasticization and Plasticizer Processes Advances in Chemistry; American Chemical Society: Washington, DC, 1965.
186
PLASTICIZATION A N D PLASTICIZER PROCESSES H0[—CHCH 0—]„H I 2
H C a
COOH
CH(CH ) 3
S
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A of polycyclic bisphenols, 4,4'-(hexahydro-4,7-methanoindan-5-ylidene)diphenol(I) and 4,4'-(2-norbornylidene) bis[2.6-dichlorophenol](II):
I
IL
Since each of these polycarbonates had exceptionally high glass transition tempera tures—256° and 290°C, respectively—it was possible to add appreciable amounts of antiplasticizers without depressing the glass transition temperatures to room temperature or lower. In addition, since the bisphenol II polycarbonate already had a relatively high tensile modulus (4.7 Χ 10 p.s.i.), it was of interest to deter mine how much this modulus could be increased. 5
To determine if the tensile properties of the commercially available polycar bonate from 4, 4 -isopropylidenediphenol were similarly affected, several of the antiplasticizers were also added to this polymer. The bisphenol itself is commonly known as bisphenol A. ,
Experimental The polycarbonates which were used in these experiments had the following molecular weights (determined ebulliometrically) : bisphenol I polymer. 20,700;bisphenol II polymer, 54,000; bisphenol A polymer, 28,200. Films containing the various additives were obtained by casting from methylene chloride by conventional techniques. Thefilms,from 1 to 3 mils in thickness, were dried at room temperature for 24 hours. Those with glass transition temperatures above 100°C. were then heated in an oven at 100° to 110°C. for 2 hours to ensure the removal of all solvent. Films with lower transition temperatures were heated under reduced pressure in an oven for 24 hours at temperatures ranging from 40° to 65°C, depending on the transition temperatures. Tensile properties (tensile strength, elongation, modulus) were measured on an Instron tensile tester (ASTM D882-61T Method A). The tensile modulus was the slope of the initial straight portion of the stress-strain diagram. The heat-distortion
Platzer; Plasticization and Plasticizer Processes Advances in Chemistry; American Chemical Society: Washington, DC, 1965.
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17.
J A C K S O N A N D CALDWELL
3.01 0
I 10
Aniiplmtkimmn
I 1 20 30 AROCLOR CONCN., %
187
I 40
I 50
Figure J. Effect of A rodor concentration on tensile moduli of bisphenol polycarbonates temperatures (2% deflection with 50-p.s.i. load) were measured in a forced-convection oven (ASTM D163 7-61) (
