K.S. Siow

Miscibility of poly(1-chloroethyl methacrylate) with various polymethacrylates

Abstract The miscibility behaviour of poly(chloromethyl methacrylate) (PCMMA) with various polymethacrylates was examined by differential scanning calorimetry and for lower critical solution temperature behaviour. PCMMA is miscible with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(n-propyl methacrylate) (PnPMA), poly(isopropyl methacrylate) (PiPMA) and poly(tetrahydrofurfuryl methacrylate) (PTHFMA), but is immiscible with poly(n-butyl methacrylate) (PnBMA). Blends of PCMMA with PMMA and PTHFMA degrade before phase separation could be induced by heating. The cloud point for other miscible blends decreases in the order PEMA > PnPMA ⋍ PiPMA . Except for PTHFMA, the trend is consistent with the general observations that the miscibility of a polymethacrylate with other polymers decreases with increasing size of the pendant group. The miscibility behaviour of PCMMA with polymethacrylates is similar to that of poly(vinyl chloride).

Miscibility and complexation behaviour of poly(styrene-co-allyl alcohol)/poly(N,N-dimethylacrylamide) and poly(styrene-co-allyl alcohol)/poly(2-ethyl-2-oxazoline) systems

Abstract The miscibility and complexation behaviour of two isomeric tertiary amide polymers, poly( N , N -dimethylacrylamide) (PDMA) and poly(2-ethyl-2-oxazoline) (PEOx), with poly(styrene- co -allyl alcohol) (SAA) containing 4.5 and 6.5 wt% of hydroxyl groups has been studied. PDMA and SAA form complexes from methyl ethyl ketone (MEK) solutions when the PDMA contents in the feed are not more than 50 and 75 wt% for SAA (4.5) PDMA and SAA (6.5) PDMA , respectively. However, they do not form complexes from tetrahydrofuran (THF) or N , N -dimethylformamide (DMF) solutions. On the other hand, PEOx does not form complexes with SAA from any of the three solvents used. We have previously reported that another isomeric tertiary amide polymer, poly( N -methyl- N -vinylacetamide) (PMVAc), can form interpolymer complexes with SAA from MEK solutions over the entire feed composition range and from THF solutions when the feed is rich in SAA. These observations show that the abilities of the three isomeric tertiary amide polymers to form complexes with SAA are in the order of PMVAc > PDMA > PEOx. FT i.r. spectroscopy studies demonstrate that intermolecular hydrogen bonding interactions contribute to the miscibility and complex formation in these blends.

Miscibility of poly(p-vinylphenol) with poly(dialkyl itaconate)s and poly(methoxycarbonylmethyl methacrylate)

The miscibility of poly(p-vinylphenol) (PVPh) with several poly(dialkyl itaconate)s and poly(methoxy-carbonylmethyl methacrylate) (PMOCMA) was studied by d.s.c. and Fourier transform infra-red (FTi.r.) spectroscopy. Poly(dimethyl itaconate) and a low molecular weight poly(diethyl itaconate) are miscible with four PVPh samples with molecular weights ranging from 1.7 to 30 kg mol−1. A high molecular weight poly(diethyl itaconate) sample is completely miscible with only two PVPh samples with low molecular weights. Poly(di-n-propyl itaconate), poly(di-n-butyl itaconate) and PMOCMA are not completely miscible with PVPh as shown by the presence of two glass transitions in some blends. FTi.r. studies show the existence of hydrogen bonding interactions between PVPh and the carbonyls of −CH2COOR in poly(dialkyl itaconate)s and the carbonyl of −COOCH3 in PMOCMA, but the interactions are weaker than the self-association of PVPh.

Thermodynamics of ionization of 2,4-dinitrophenol in water-dimethylsulfoxide solvents

The ionization constants of 2,4-dinitrophenol were measured in water-dimethylsulphoxide solvent mixtures at five temperatures ranging from 20 to 40°C. The enthalpy and entropy contributions to the ionization process are discussed. The results indicate that in water-rich solvent mixtures the ionization process is controlled by the entropy factor while in the dimethylsulphoxide-rich solvent mixtures it is controlled by the enthalpy factor.

Complexation between poly(hydroxyether of bisphenol-A) and three tertiary amide polymers

Abstract The complexation behaviour between poly(hydroxyether of bisphenol-A) (phenoxy) and three isomeric tertiary amide polymers, namely poly(N-methyl-N-vinylacetamide) (PMVAc), poly(N,N-dimethylacrylamide) (PDMA) and poly(2-ethyl-2-oxazoline) (PEOx), has been studied. Phenoxy forms interpolymer complexes with PMVAc and PDMA from tetrahydrofuran solutions over the entire feed composition range. However, complexation does not occur between phenoxy and PEOx from THF solutions, indicating a weaker intermolecular association in the phenoxy/PEOx blends than those in the phenoxy/PMVAc and phenoxy/PDMA blends. When using N,N-dimethylformamide as the solvent, only miscible blends are formed between phenoxy and all three tertiary amide polymers. Infra-red spectroscopic studies provide evidence of intermolecular hydrogen bonding between the hydroxyl groups in phenoxy and the carbonyl groups in tertiary amide polymers. The frequency shifts for the phenoxy hydroxyl group hydrogen bonded to the three tertiary amide polymers decrease in the order of PMVAc → PDMA → PEOx.

Interpolymer complexes in the poly(styrene-co-allyl alcohol)/poly(N-methyl-N-vinylacetamide) system

Abstract Poly(styrene-co-allyl alcohol) (SAA) with hydroxyl contents of 4.5 and 6.5 wt% can form intermolecular complexes with poly(N-methyl-N-vinylacetamide) (PMVAc) depending on the nature of the solvent(s) and the feed compositions that are used. When methyl ethyl ketone was used as the solvent, complexation between SAA and PMVAc occurred at all feed compositions, but when tetrahydrofuran was used as the solvent, complexation occurred only when the feed was rich in SAA. However, only miscible blends were formed from N,N-dimethylformamide, a strong hydrogen bond breaking solvent. The compositions of the complexes are in the range of 50–70 mol% and 55–74 mol% of PMVAc for the SAA (4.5) PMVAc and SAA (6.5) PMVAc systems, respectively. Fourier transform infra-red spectroscopic studies showed the existence of hydrogen bonding interactions in the blends.

Miscibility of polymethacrylates with poly(p-methylstyrene-co-acrylonitrile)

Abstract The miscibility of five polymethacrylates with poly(p-methylstyrene-co-acrylonitrile) (pMSAN) has been studied. Poly(methyl methacrylate), poly(ethyl methacrylate), poly(n-propyl methacrylate) and poly(n-butyl methacrylate) are miscible with pMSAN over certain copolymer composition ranges but poly(isopropyl methacrylate) is immiscible with pMSAN. The phase behaviour of polymethacrylate/pMSAN blends is, in general, similar to that of the corresponding blends with poly(styrene-co-acrylontrile). Various segmental interaction parameters have been evaluated and compared with the corresponding parameters involving the styrene segment.

Solubility parameters of poly(α-methylstyrene-co-acrylonitrile) from gas−liquid chromatography

Abstract Solubilities of fourteen polar and non-polar solvents in poly(α-methylstyrene -co-acrylonitrile) have been measure by the gas chromatographic method over the temperature range 165–195°C. The Flory—Huggins χ parameters, partial molar heats of mixing (Δ H ∞1) and heat solution (Δ Hs) were calculated and the infinite-dilution solubility parameter (δ∞2) for the polymer was estimated following the method of Di Paola-Baranyi and Guillet. At 180°C (midpoint of the temperature range investigated), δ∞2 was found to have a value of 8.0 (cal/ml)1/2. By linear extrapolation, the χ parameter at 25°C was also estimated, which yielded a value of 9.9 for δ∞2 at 25°C.

Miscibility of poly(2-fluoroethyl methacrylate) and poly(1,1,1,3,3,3-hexafluoroisopropyl methacrylate) with various polymethacrylates

Abstract The miscibility behaviour of poly(2-fluoroethyl methacrylate) (P2FEMA) and poly(1,1,1,3,3,3-hexafluoroisopropyl methacrylate) (PHFPMA) with various polymethacrylates was studied by differential scanning calorimetry and for lower critical solution temperature ( LCST ) behaviour. Both P2FEMA and PHFPMA are miscible with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA) and poly(tetrahydrofurfuryl methacrylate) (PTHFMA), but are immiscible with poly(n-propyl methacrylate) (PnPMA), poly(isopropyl methacrylate) (PiPMA), poly(n-butyl methacrylate) (PnBMA) and poly(cyclohexyl methacrylate) (PCHMA). Phase separation could be induced by heating for blends of P2FEMA with PMMA and PEMA. For PHFPMA, only PHFPMA/PEMA blends showed LCST behaviour. The miscibility behaviour of P2FEMA and PHFPMA is similar to that of poly(2-chloroethyl methacrylate).

Miscibility behaviour of polymethacrylates with poly(styrene-co-methacrylonitrile)

Abstract The miscibility behaviour of various poly(styrene- co -methacrylonitrile) (SMAN)/polymethacrylate blends was studied using differential scanning calorimetry. SMAN is miscible with poly(ethyl methacrylate) (PEMA), poly(n-propyl methacrylate) (PnPMA) and poly(isopropyl methacrylate) (PiPMA) over certain copolymer composition ranges, but is immiscible with poly(n-butyl methacrylate) (PnBMA) and poly(isobutyl methacrylate) (PiBMA). The width of the miscibility window decreases with increasing size of the pendent ester group of the polymethacrylate, and is wider than that of the corresponding poly(styrene- co -acrylonitrile) blend system. Various segmental interaction parameters are calculated using a binary interaction model.