Abstract
1, 2-di (m-methylphenoxy) ethane-p, p′-dicarboxylic acid (A) was derived from m-cresol by the similar procedure as 1, 2-di (o-methylphenoxy) ethane-p, p′-dicarboxylic acid (B) described in the previous paper. The former is a new compound as well as the latter. The polyether-ester (I) having the following chemical formura was then prepared by the polycondensation of the dimethylester of (A) with ethyleneglycol.
The effects of the position of CH3 group in the benzene ring of (I) on the physical properties and fiber-forming property were studied in comparison with those of the CH3 group in poly (ethylene-1, 2-di (o-methylphenoxy) ethane-p, p′-dicarboxylate) (II) reported in the previous paper.
(II) crystallizes from the melt on cooling, while (I) solidifies in glassy state without crystallization. The amorphous (I) crystallizes by immersing it in methanol at 50°C for about 5 hrs. It's melting point is 157°C_??_162°C, while that of (II) is 238°C_??_240°C (measured by the hot plate method). The melting point ratio (absolute temperature) of (I) to (II) is equal to that of dimethylester of (A) to (B). The glass transition temperature of (I) measured by a differential thermal analysis is 52°C. It is also lower than that of (II); 72°C.
The lowering of crystallinity, the melting point and glass transition temperature of (I) is due to the inhibited co-planarity of the ethylene-ester with benzene ring by a steric effect of the methyl group on a carbonyl group.
However, (I) can be melt-spun and the tensile strength of drawn fiber of (I) is a little inferior to that of (II) but is still within a range of practical use. The melt-spun fiber of (I) is drawn more readily as compared with (II).
The fiber period for (I) is calculated as 36.2 A from X-ray diffraction patterns of fiber (I) drawn into 7 times length and annealed at 120°C for half hour. The value is about double of that of (II); 18.5 A as well as that of the basic polymer having no methyl group; 18.7 A. This means that the conformation of molecular chain is not planar at carbonyl-benzene bond and the twisted state returns back over two chemical repeating units.
In conclusion, it may be interpreted that the differences in above-mentioned properties between (I) and (II) arise from the ortho effect of methyl group and carboxylate group in (I).
