Inherent viscosity, poly

Inherent Viscosities of Poly(Methyl Vinylsalicylates) Polymer inh... 

The polymers of 1,4-hexadienes have unusually wide molecular weight distributions. This is illustrated by the gel permeation chromatogram of the methanol-insoluble fraction of poly(5-methyl-1,4-hexadiene) in tetrahydrofuran (Figure 9). The polymer was obtained in 82% conversion and had an inherent viscosity of 2.1 dl./g. in toluene at 25°C. 

DMAc at 0 to 5°C for 8 h and fluorine-containing poly(o-hydroxy amides) (27) having an inherent viscosity of 0.40 dl/g is obtained (Scheme 15).25... 

In the second stage, the polyfo-hydroxy amides) (27) are subjected to thermal cyclodehydration to convert to poly(benzoxazole) (28). The conversion requires 15 to 20 h at 250°C in vacuo for its completion. The resulting poly(benzoxazole) (28) has an inherent viscosity of 0.49 dl/g. 

It was found that the reaction conditions which were optimized for the synthesis of poly(arylene siloxanylenes) (43) could be employed for the synthesis of siloxane-modified poly-(arylene carbonates). 2,4,6-Trimethylpyridine (collidine) was selected as the most suitable of all catalysts investigated (43) for the synthesis of the siloxane modified poly(arylene carbonates). Properties of polymers prepared by this method are given in Table I. In comparision to the phosgene-catalyzed homo-polycondensation of bis-silanols, III, the inherent viscosities... 

Poly(arylene ether l,2,4-triazole)s were synthesized from the reaction of 3,5-di(4-hydroxyphenyl)-4-phenyl-1,2,4-triazole with three different activated aromatic difluoro monomers [34,35]. The polymer from the triazole bisphenol and 1,4-di(4-fluorobenzoyl)benzene exhibited an inherent viscosity of 3.40 dL/g (0.5% solution in m-cresol at 25 °C), a Tg of 216 °C and a Tm of 377 °C [35]. Solution cast amorphous unoriented thin films of this polymer gave 23 °C tensile strength, modulus and elongation of 87.6 MPa, 2.7 GPa and 7.8% respectively. No work was performed to induce crystallinity in the film. 

A poly(arylene ether phenylquinoxaline) of structure 14 was prepared by the aluminum chloride catalyzed reaction of 6,6 -bis[2-(4-phenoxyphenyl)-3-phenylquinoxaline] and isophthaloyl chloride in 1,2-dichloroethane [51]. The polymer had an inherent viscosity of 1.29 dL/g and a Tg of 224 °C. A polymer of the same chemical structure was prepared from the reaction of 3,3, 4,4 -tetraaminobiphenyl with l,3-bis(phenylglyoxalyl-4-phenoxy-4 -benzoyl)-benzene that gave a Tg of 239 °C [16], significantly higher than that prepared by the electrophilic route. In addition, a polymer of the same chemical structure (third polymer in Table 3) prepared via nucleophilic substitution exhibited a Tg of 240 °C. 

Fig. 3. Phase diagram for solutions of poly-p-benzamide in dimethyl acetamide/lithium chloride I0). Polymer inherent viscosity 1.18...

Adhesion of Coatings. Except for K-l polycarbonate [4,4 -(2-nor-bornylidene)diphenol polycarbonate] (4), an experimental polymer (inherent viscosity 0.85), all the coatings were prepared with commercial products EAB-381-0.5 and EAB-381-20 cellulose acetate butyrates from Eastman Chemical Products, Inc. VYHH vinyl chloride (87%)/vinyl acetate (13%) copolymer from Union Carbide Corp. Butvar B76 poly-(vinyl butyral) from Shawinigan Resins Corp. Plexiglas V poly (methyl methacrylate) from Rohm and Haas Co. Dylene P3I polystyrene from... 

Synthesis of the 2G-based copolymer can be somewhat more difficult than synthesis of the analogous 4G-based copolymer. If the ethylene glycol and dimethyl terephthalate monomers are prereacted to form bis (2-hydroxy ethyl) terephthalate, and this product is then copolymerized with poly(tetramethylene ether) glycol to form the block copolymer using tetrabutyl titanate as the transesterification catalyst, the reaction proceeds readily and copolymer of high inherent viscosity is easily obtained. If the ethylene glycol monomer is not prereacted and tetrabutyl titanate is again used as the transesterification catalyst, the copolymerization proceeds more slowly and a block copolymer of lower inherent viscosity is usually obtained. 

Tg taken as midpoint in baseline transition at a heating rate of 10°C/min. b Inherent viscosity, (lnijr i)/c, where c = 0.25 g/dL, in benzene. c Rohm and poly (methyl methacrylate). Plexiglas type V-811. d Prepared by radical suspension bead polymerization by J. L. Tucker. Dissolved in benzene, precipitated, and freeze dried from benzene. Numbers in parentheses are the percentages of styrene determined by NMR. 

Solution viscosities were determined at elevated temperatures on purified polyaldehyde samples, and inherent viscosities as high as 0.85 have been obtained. Isotactic poly-ft-butyraldehyde solutions in purified tetrahydro-naphthalene are stable in the viscometer at 140° C. for at least 2 hours. 

The inherent viscosity values have been compared with end group determinations of the acetate end groups of completely acetylated poly-n-butyralde-hyde. For this purpose, the intensity of the carbonyl band of the acetate end groups (5.72 p) was determined by infrared and was related to an internal standard giving what we call the end group ratio (15.72 4.75 ) The end... 

Figure 5. Solution viscosity vs. end group relationship for poly-n-butyraldehyde. The inherent viscosity was measured in 0.5% tetrahydronaphthalene at 140° C.

Solution viscosities are involved in quality control of a number of commercial polymers. Production of poly(vinyl chloride) polymers is usually monitored in terms of relative viscosity (tj/tjo) while that of some fiber forming species is related to IV [inherent viscosity, c ln(> /)/ )]. The magnitudes of these parameters depends primarily on the choices of concentration and solvent and to some extent on the solution temperature. There is no general agreement on these experimental conditions and comparison of such data from di I ferent manufacturers is not always straightforward. 

P. R. Dvomic, S. D. Vignevic and M. N. Govedarica, On the synthesis of poly(p-phenylene terephthalamide). Effect of polymerization reaction mixture concentration and the efficiency of mixing on the inherent viscosity of the polymer product, J. Serb. Chem. Soc., 58 (1993) 357-370. 

The preceding discussion applies to a polyamide which precipitates. Figure 5 shows that for poly(sebacyl piperazine) (first structure. Table II), which remains dissolved in the organic solvent, there are likewise coincident peaks in the plots of inherent viscosity and yield vs. the concentration of acid chloride. 

The solid-phase method of building up polyformals is applicable only to high-melting polymers. The required melting point is not known, but the poly-formal of trarw-l,4-cyclohexanediol melted at 206°—10° C. and that of the cis-/ trans- mixture of 2,2,4,4-tetramethyl-l,3-cyclobutanediol melted appreciably higher. The solution method did not appear to be applicable to building up the polyformals of these two diols, since inherent viscosities below 0.4 were obtained. The solution method may be most applicable to primary diols, such as cyclohexanedimethanol and decanediol, which gave polyformals with inherent viscosities of 0.9. 

In these experiments with tetramethylcyclobutanediol, it was found that methanedisulfonic acid gave higher polyformals than the other catalysts. Inherent viscosities up to 1.7 were obtained, whereas values of only 0.8 to 0.9 resulted with camphorsulfonic acid or p-toluenesulfonic acid and 0.7 when perchloric acid was used. It was necessary to use 0.002 to 0.005 equivalent of camphorsulfonic acid or toluenesulfonic acid per mole of diol in order to obtain the poly formal, but 0.001 equivalent of perchloric acid or 0.001 to 0.002 equivalent (0.0005 to 0.001 mole) of methanedisulfonic acid was sufficient to catalyze the polymerization in the various solvents. When appreciably less catalyst was used, the polymers did not build up, and when appreciably more was used, brown polymers were obtained. 

Polymers 250 and 251, formed by coordination of Ru11 complexes to the preformed 2,6-poly(bis(benzimidazol-2-yl)pyridine), showed a strong enhancement of absorption and photosensitivity in the visible region relative to the unmetalated polymer.141 The metalated polymers, with ca. 90% of the coordination sites occupied, showed an inherent viscosity of 1.8 dLg-1. Although the polymers have low conductivities (ca. 10 10Scm-1), they exhibited higher photocurrents than the organic precursor polymer. 

Some all-aromatic poly (thiol esters) have also been prepared by this method (34). There is also a continuous process for interfacial condensation polymerization by which poly (thiol esters) with high inherent viscosities have been produced (27). 

Applications. Poly (thiol esters) can be good starting materials for producing fibers when the esters have an inherent viscosity 77 >0.3 g/dl (27) or >0.75 g/dl (16). They can be cold-drawn to oriented fibers involving a three- to fivefold or even higher increase in length. 

Films can be cast from poly (thiol esters) with inherent viscosities 77 > 0.5 g/dl (16), but no data about their properties are available. 

H2SO4. Inherent viscosities as shown in Table IV are low, being less than 0.5 dl/g., indicating low molecular weight. While films could be prepared from the poly (amic adds), which were converted to polyimides on heat treatment (200-250°C for several hours), they were very brittle and broke on handling. This is not surprising in view of the low inherent viscosity (<0.5) for these polymers. Wallach (9) has reported that polyimides with inherent viscosities of less than 1.0 have negligible physical property levels. 

A polymer corresponding to VII, but having N-phenyl groups, has been reported to be fiber forming (7). Also, the conversion of poly—p-phenyleneterephthalamide to an N-alkylated (Cj-ig) product has been described (8) however, the Inherent viscosity values for these polymers are extremely low (< 0.15), suggesting that considerable degradation of the polymers probably occurs during their synthesis. 

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