Synthesis and characterization of segmented copolymers of polystyrene and thermotropic liquid crystalline poly(4-oxybenzoate-co-2,6-oxynaphthoate)

Figures & data

Table 1 Yields and compositions of segmented copolymers 3–5 prepared by condensation of PS precursor polymer with HBA and HNA.

Copolymer	Feeding wt.% of PS	Yield (%)	Composition (wt.%)
			Fraction a	Fraction b	Fraction c
3	25	82.5	63.2	26.3	10.5
4	50	85.2	58.6	36.3	5.1
5	75	84.0	80.7	17.4	1.9

Scheme 1 Separation procedures for copolymers 3–5.

Scheme 2 Synthesis of copolymers 3–5.

Figure 1 FT-IR spectra of (A) PS, (B) copolymer 3a, (C) copolymer 3b, (D) copolymer 3c, and (E) LCP.

Table 2 Characterization of copolymers 3a–5a those were soluble in THF.

Polymer	Mn	PDI	T g (°C)	T d ^a (°C)
PS	26,918	1.29	97.0	363.3
3a	33,822	1.46	99.5	370.1
4a	31,251	1.46	102.1	365.5
5a	33,328	1.45	101.5	378.4
Note: ^a T d was the decomposition temperature obtained by TGA.

Figure 2 DSC thermograms (10 °C/min) of segmented copolymers 3b–5b, PS and LCP.

Figure 3 Polarized optical micrographs of (a) 3b and (b) LCP.

Figure 4 TGA thermographs of 3b–5b.

Table 3 Characterization of copolymers that were soluble in 4-chlorophenol at 120 °C (3b–5b).

Polymer	IV^b (dl/g)	T g (°C)	T m (°C)	ΔH (mJ/mg)	T d1 ^a (°C)	wt. loss (%)	T d2 ^a (°C)	wt. loss (%)
PS	0.067	97			363.3
3b	0.140	103.9	267.3	2.8	300.6	19.42	502	33.5
4b	0.150	101.8	259.9	2.6	316.0	21.84	490	30.36
5b	0.072	93.6	259.2	2.5	355.6	25.80	512	31.88
LCP	0.002	83.5	270.6	1.9	495.3
Notes: ^a T d is the decomposition temperature obtained by TGA.^bIV is obtained by dissolution of segmented copolymer in pentafluorophenol at 70 °C.

Figure 5 X-ray diffraction trace of segmented copolymer 3b.