Sedimentation velocity measurements close to the upper critical solution temperature and at θ-conditions: polystyrene in cyclopentane over a large concentration interval

Sedimentation velocity measurements on polystyrene (M = 110 000) in cyclopentane over an extended concentration region and from 5°C (close to the upper critical solution temperature) to 40°C are reported. The concentration dependence parameter (k_s)_w increases from 2 to 5°C to 27 at 40°C. For all temperatures except 5°C, $\text{s}{}_0\text{s}$ vs. w[η]_w shows an upward curvature at w[η]_w ≈ 1; at 5°C, on the other hand, $\text{s}{}_0\text{s}$ is independent of concentration over the region considered. Furthermore, measurements have also been performed at 20°C (θ-conditions) over a large concentration interval for the molecular weights M = 20 400, 390 000 and 950 000. The parameters s₀ and (k_s)_w were both found to be proportional to $\text{M}\text{?}{}^{\mathrm{1/2}}{}_{\mathrm{w}}$. In the ‘hydrodynamically normalized’ plot $\text{s}{}_0\text{s}$ vs. w[η]_w the sedimentation behaviour can approximately be represented by a single curve for all the molecular weights.     

Isothermal crystallization of poly(ethylene-terephthalate) of low molecular weight by differential scanning calorimetry: 1. Crystallization kinetics

The isothermal crystallization of poly(ethylene-terephthalate) (PETP) fractions, from the melt, was investigated using differential scanning calorimetry (d.s.c.). The molecular weight range of the fractions was from 5300–11750. Crystallization temperatures were from 498–513 K. The dependence of molecular weight and undercooling on several crystallization parameters has been observed. Either maxima or minima appear at a molecular weight of about 9000, depending on the crystallization temperature. The activation energy values point to the possibility of different mechanisms of crystallization according to the chain length. A folded chain process for the higher $\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$ chains and an extended chain mechanism for the lower $\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$ chains. The values of the Avrami equation exponent n vary from 2–4 depending on the crystallization temperature; non-integer values are indicative of heterogeneous nucleation. The rate constant K depends on T_c and $\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$, showing maxima related to the T_c used. The plot of log K either vs. (ΔT)^?1 and (ΔT)^?2 or $\text{T}{}_{\mathrm{<mtext>m</mtext>}}\text{T(ΔT)}$ and $\text{T}{}^2{}_{\mathrm{<mtext>m</mtext>}}\text{T(ΔT)}{}^2$ is linear in every case.     

Solid and liquid state relaxations in spin-labelled poly)ethylene glycol) at high temperatures (T>Tg)

Free and covalently bonded (esterified) nitroxyl radicals experienced in poly(ethylene glycols) (PEG; $\text{M}\text{?}{}_{\mathrm{n}}$ 200–22 000) at temperatures T >T_g several different isotropic rotational relaxation regions. As a first approximation it was assumed, that in the polyglycols $\text{M}\text{?}{}_{\mathrm{n}}\text{? 1000}$ there are at least three rotational relaxation regions: the liquid state (I), the melting state (II) and the solid state (III). The existence of the fourth region, the frozen solid state (IV), was also concluded. The existence of the relaxation region (II) indicated the close interaction between radicals and the crystalline phase. The order of rotational activation energies (E_a) was E^II_a >E^III_a >E^I_a >E^IV_a ($\text{M}\text{?}{}_{\mathrm{n}}\text{? 1000}$). In the polymer melts (I) E_a values of free and bonded radicals first diminished as a consequence of the decrease of the end group effect and they achieved constant high molecular weight values (～15 and 25 kJ respectively). E_a changed in the solid state as a function of $\text{M}\text{?}{}_{\mathrm{n}}$ principally in the same manner except of the higher numerical values (～40 kJ).E_a of free and covalently bonded radicals in the transition region (II) gained a maximum at $\text{M}\text{?}{}_{\mathrm{n}}$ 1550 (125 and 170 kJ) and another at $\text{M}\text{?}{}_{\mathrm{n}}\text{> 9500}$ (130 and 165 kJ) expressing the high degree of order in these polymers in the solid state.The results obtained correlated well with the proton magnetic resonance measurements but they did not correlate with the amorphous dielectric relaxation measurements.It was concluded that the following factors may affect the rotational relaxations of nitroxyl radicals in PEG: the free volume of the polymer, the crystallinity, the chain packing and the end-group effect. The segmental character of the relaxation process was clearly indicated.     

Copoly(m,p-chloromethylstyrene-50% styrene): Copolymer molecular weights,fractionation and derivatization

Copolymerization of an equimolar mixture of m,p-chloromethylstyrene ($\text{M}$₁) and styrene ($\text{M}$₂) was carried out in chlorobenzene in the presence of AIBN at 80°C. Molecular weight analysis (by g.p.c.) of the resulting polymer samples was performed at various conversions. $\text{M}\text{?}{}_{\mathrm{<mtext>w</mtext>}}$, $\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$, and ($\text{M}\text{?}{}_{\mathrm{<mtext>w</mtext>}}\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$) value of 21 300, 13 800 and 1.54 were obtained at 8.9% conversion. At higher conversions, the value of $\text{M}\text{?}{}_{\mathrm{<mtext>w</mtext>}}$ remained effectively constant while $\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$ decreased to 9200 at ca. 80% conversion, and then increased to 12 000 at about 100% conversion (16 h), and to 13 700 if the polymer solutions were maintained at 80°C for an additional 44 h. These results suggest that, although the termination step initially involves the combination of polymer radicals, at high conversions a large number of very low molecular weight, and unsaturated, polymer molecules are formed possibly by disproportionation involving polymer radicals and primary radicals. The unsaturated polymer molecules are subsequently polymerized by growing polymer radicals towards the end of the polymerization. It was noticed that further reaction occurred after complete depletion of monomer, involving radical attack on the unsaturated polymer molecules. Other reactions including chain transfer to polymer will also be important at high polymer concentrations. A copolymer of $\text{M}$₁ and $\text{M}$₂ was separated into four fractions on a preparative scale, and molecular weight analysis of the resulting polymer samples provided more evidence of the above interpretation. G.p.c. analysis of several derivatives of a copolymer of $\text{M}$₁ and $\text{M}$₂ showed that most molecular weights were much lower than that of the starting polymer. These results in some cases may reflect the chemical or dimensional changes introduced into the polymer molecules during derivatization.     

Comparison of the unperturbed dimension of polystyrene for endothermal and exothermal heats of dilution within the same system

Light scattering measurements for two samples of polystyrene (I, M_w = 2.15 × 10⁵; II, M_w = 2.5 × 10⁶) were performed in the iso-refractive mixed solvent dimethoxymethane-diethyl ether. For sample I the temperature dependence of the second osmotic virial coefficient A₂ was determined for three constant compositions of the mixed solvent. In the range ?30° to +25°C the three curves run practically parallel and exhibit a maximum at approximately ?10°C. For the volume fraction of 0.7 diethyl ether in the mixed solvent, an endothermal theta-temperature θ₊ was found at ?27.0° ± 1.5°C and θ_?, the exothermal theta-temperature, at ?5.0 ± 1°C. The investigation of sample II in the abovementioned solvent confirmed the observed θ_?-temperature and displayed a higher exothermicity compared with I. Similarly to the temperature variation of A₂, the chain dimensions of II, determined from the angular dependence of the scattered light, run through a maximum. The unperturbed dimensions in the mixed solvent are found to be: $\text{r}{}_{\mathrm{w}}\text{= 448 ± 5}\text{A}\text{?}$ at θ₊ = ?27°C and $\text{r}{}_{\mathrm{w}}\text{= 443 ± 5}\text{A}\text{?}$ at θ_? = ?5°C, as compared with $\text{r}{}_{\mathrm{w}}\text{= 420 ± 10}\text{A}\text{?}$ at θ₊ = +33°C in cyclohexene. The inter-relation of the chain expansion coefficient and A₂ is quantitatively described by the Zimm-Stockmayer-Fixman equation over the entire range of heats of dilution.     

Polymerization of poly(dimethylsiloxane) macromers: 1. Copolymerization with styrene

The synthesis and characterization of methacrylate-ended macromers ($\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$ 500 to 10 000) and their copolymerization with styrene (M₂) is described. The experimental errors in the values of the reactivity ratios r₁ render them meaningless. Values of r₂ can be determined with more precision and increase from 1.06 to 1.55 as the molecular weight of the macromer increases. This behaviour is due to steric effects, not diffusion-controlled propagation. It is shown that the assumptions that $\text{1 > r}{}_1\text{[}\text{M}{}_1\text{]}\text{[}\text{M}{}_2\text{]}$ and $\text{r}{}_2\text{>}\text{[}\text{M}{}_1\text{]}\text{[}\text{M}{}_2\text{]}$ are only valid for macromers of $\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}\text{> ca. 10 000}$.     

Molecular weight distribution and stereoregularity of polypropylenes obtained with Ti(OC4H9)4Al2(C2H5)3Cl3 catalyst system

The effects of temperature and catalyst homogeneity on the molecular weight distribution (MWD) and stereochemical regulation of polypropylenes produced by $\text{Ti(OC}{}_4\text{H}{}_9\text{)}{}_4\text{Al}{}_2\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{Cl}{}_3$ system have been investigated. The MWD of polymers obtained at temperatures below 21°C were unimodal and narrow ($\text{M}\text{?}{}_{\mathrm{w}}\text{M}\text{?}{}_{\mathrm{n}}\text{?2.0}$), whereas those obtained at temperatures higher than 31°C were bimodal with one narrow distribution and the other broad one ($\text{M}\text{?}{}_{\mathrm{w}}\text{M}\text{?}{}_{\mathrm{n}}\text{=18}$) at higher molecular weights. The existence of two different types of catalyst, one soluble with homogeneous catalytic centres and the other insoluble with heterogeneous catalytic centres was found in the polymerization at 41°C. At temperatures below 21°C only soluble catalyst was present and produced isotactic polypropylenes with [m]=0.65. The isospecific nature of soluble titanium-based catalyst is greatly contrasted to the syndiospecific nature of soluble vanadium-based catalyst.     

Random-coil configurations of alicyclic polyformals

A sample of poly (trans-1,4-cyclohexylene-dimethylene-oxymethylene oxide) (PTCDM) was synthesized by condensation of trans-1,4-cyclohexane dimethanol and paraformaldehyde using p-toluene sulphonic acid as catalyst. A fraction having M_n=6500 and a melting point of 86°C was isolated and purified; its n.m.r. spectrum does not change with temperature in the range 20°–50°C which indicates a rigid distribution of methylene substituents in the cyclohexane ring; its dipole moment, measured in benzene solution at several temperatures between 20° and 60°C, yielded values of $\text{D}{}_{\mathrm{n}}\text{=}\text{[μ}{}^2\text{]}\text{nm}{}^2\text{=0.17–0.21}$ and a temperature coefficient dln $\text{{gm}{}^2\text{}}\text{d}\text{T}\text{= 5.5 × 10}{}^{\mathrm{?3}}\text{K}{}^{\mathrm{?1}}$, similar to those reported in the literature for acyclic polyformals. Agreement between experimental and calculated (using rotational isomeric states theory) values is satisfactory.     

Thermomechanical heat of deformation studies on cis-polybutadiene

Thermomechanical heat of torsional deformation measurements have been made on crosslinked cis-polybutadiene by means of a Calvet microcalorimeter operated at 30°C. When corrected for volume changes utilizing the Gaussian statistical theory of elasticity, the data gave a value for the relative energy contribution to the torsional couple, $\text{M}{}_{\mathrm{e}}\text{M}$, of 0.14 ± 0.02. Measurements were also made on a sample subjected to simple tensile deformations. The relative energy contribution to the tensile force ($\text{f}{}_{\mathrm{e}}\text{f}$) was found to agree within experimental error with the value obtained for $\text{M}{}_{\mathrm{e}}\text{M}$, and the two results gave an average value for din $\text{〈r}{}^2{}_0\text{〉}\text{d}\text{T}$ of 4.1 × 10^?4 K^?1.     

Properties of extremely high molecular weight polystyrene in solution

Extremely high molecular weight polystyrenes with a $\text{M}\text{?}{}_{\mathrm{w}}$ in the range 10.8 × 10⁶ to 2.2 × 10⁷ were prepared by emulsion polymerization initiated with a heterogeneous initiator at 30°C, which has a ‘living character’. Samples of polystyrene were characterized by light scattering and viscometry in toluene and benzene at 25°C, and in θ-solvent cyclohexane at 34.8°C. Also determined were the relationships of mean-square radius of gyration 〈s²〉 (m²) and the second virial coefficient A₂ (m³ mol kg^?2) on the molecular weight, which for toluene and benzene are described in equations: Toluene (25°C) $\text{〈s}{}^2\text{〉=1.59 × 10}{}^{\mathrm{?23}}\text{M}\text{?}{}_{\mathrm{w}}{}^{1.23}$; $\text{A}{}_2\text{=4.79 × 10}{}^{\mathrm{?3}}\text{M}\text{?}{}_{\mathrm{w}}{}^{\mathrm{?0.63}}$; Benzene (25°C) $\text{〈s}{}^2\text{〉=1.23 × 10}{}^{\mathrm{?22}}\text{M}\text{?}{}_{\mathrm{w}}{}^{1.20}$; $\text{A}{}_2\text{=2.59 × 10}{}^{\mathrm{?3}}\text{M}\text{?}{}_{\mathrm{w}}{}^{\mathrm{?0.59}}$. The parameters in the Mark-Houwink-Sakurada equation were established, for extremely high molecular weight polystyrene in toluene and in benzene, at 25°C into the form giving for $\text{[η] (}\text{m}{}^3\text{kg}{}^{\mathrm{?1}}\text{): [η] = 8.52 × 10}{}^{\mathrm{?5}}\text{M}\text{?}{}_{\mathrm{w}}{}^{0.61}$; $\text{[η] = 1.47 × 10}{}^{\mathrm{?4}}\text{M}\text{?}{}_{\mathrm{w}}{}^{0.56}$. The mentioned relations, as well as the obtained values of Flory parameter ?₀ and of ratio $\text{[η]}\text{M}\text{?}{}_{\mathrm{w}}{}^{0.5}$ were compared with solution properties of high molecular weight polystyrene with narrow molecular weight distribution prepared by anionic polymerization by Fukuda et al.     

Cyclization dynamics of polymers: 9. The effect of polymer concentration on the slowest internal relaxation mode of a labelled polystyrene chain

A combination of steady-state and fluorescence decay techniques permits one to measure the dynamics of end-to-end cyclization of a polymer chain substituted at both ends with pyrene groups. In the limit of low concentration, the rate constant for cyclization, k_cy, can be identified with the slowest relaxation rate $\text{τ}{}_1{}^{\mathrm{?1}}$ of a Rouse—Zimm chain. Experiments are reported which allow k_cy to be examined for two chain lengths of polystyrene substituted on both ends with pyrene groups. These chains have $\text{M}\text{?}{}_{\mathrm{n}}\text{= 9200}$ and 25 000 ($\text{M}\text{?}{}_{\mathrm{w}}\text{M}\text{?}{}_{\mathrm{n}}\text{? 1.15}$). Added unlabelled polystyrene polymer [PS] causes $\text{k}\text{?}{}_{\mathrm{<mtext>cy</mtext>}}$ to decrease in cyclohexane just above the θ-temperature, whereas in toluene, a good solvent, k_cy is largely unaffected, even at [PS] concentrations of 50 wt%. These results are explained in terms of frictional effects—hydrodynamic screening—dominating in the poor solvent, whereas other factors tend to have offsetting effects in the good solvent.     

Self-diffusion of poly(ethylene oxide) in aqueous dextran solutions measured using FT-pulsed field gradient n.m.r.

Transport in ternary polymer₁, polymer₂, solvent systems has been investigated using an n.m.r. spin-echo technique. The dependence of the self-diffusion coefficient of poly(ethylene oxide) polymers on the concentration and molecular size of dextran in aqueous solution has been measured. Monodisperse poly(ethylene oxide) fractions ($\text{M}\text{?}{}_{\mathrm{w}}\text{=7.3×10}{}^4$, 2.8·10⁵ and 1.2·10⁶) and dextrans ($\text{M}\text{?}{}_{\mathrm{w}}\text{=2·10}{}^4$, 1·10⁵ and 5·10⁵) have been employed over a range of concentration up to the miscibility limit in each system. It is found that when the molecular size of the diffusant is commensurate with or exceeds that of the matrix polymer, a relationship of the form: $\text{(}\text{D}\text{D}{}_0\text{)}{}_{\mathrm{<mtext>PEO</mtext>}}\text{=}\text{exp}\text{?k(C[η])}$ is applicable, where C[η] refers to the dextran component and is considered to describe the extent of coil overlap in concentrated solution. ($\text{D}\text{D}{}_0$) is independent of the molecular size of the poly(ethylene oxide), at least in the range studied (M_w<300 000).     

Cloud-point curves of the polystyrene-cyclohexane system near the critical point

Cloud-point curves for solutions of five polystyrene samples, including three well-fractionated polystyrenes, in cyclohexane have been examined near their critical points. Even for a solution of polystyrene characterized by $\text{M}{}_{\mathrm{w}}\text{M}{}_{\mathrm{n}}\text{<1.03}$, the critical point determined by the phase-volume method is generally situated on the right hand branch of the cloud-point curve. The precipitation threshold concentration is appreciably lower than the critical concentration, while the threshold temperature slightly deviates from the critical temperature. The agreement of the precipitation threshold point with the critical point has been found for a solution of polystyrene characterized by M_w=20×10⁴ and $\text{M}{}_{\mathrm{w}}\text{M}{}_{\mathrm{n}}\text{<1.02}$ in cyclohexane. The η(φ) function derived from critical miscibility data is expressed by $\text{χ(φ) = 0.2798+}\text{67.50}\text{T}\text{+0.3070φ+0.2589φ}{}^2$, which yields θ of 33.2°C and ψ₁ of 0.22.     

Temperature dependence of polymer chain dimensions in the polystyrene-cyclopentane system

The limiting viscosity number in polystyrene-cyclopentane system has been determined over the temperature range of θ_u to θ_l in which θ_u and θ_l are the θ or Flory temperature for the upper and lower critical solution temperatures. The temperature coefficient of unperturbed mean square end-to-end distance observed for the polystyrene (M_w=20×10⁴, $\text{M}{}_{\mathrm{w}}\text{M}{}_{\mathrm{n}}\text{<1·06}$ and M_w=67×10⁴, $\text{M}{}_{\mathrm{w}}\text{M}{}_{\mathrm{n}}\text{<1·10}$) in cyclopentane is negligibly small. The observed temperature dependence of the polymer chain dimension over the temperature range of θ_u=19·6° to θ_l=154·2°C shows a parabolic curve with a maximum in the neighbourhood of 90°C and is qualitatively interpreted by the free volume theory of polymer solution, which gives a new χ₁-temperature function.     

Ultra-high modulus polyethylene. 1 Effect of drawing temperature

Drawing behaviour and the properties of ultra-drawn high density polyethylene have been investigated as a function of the drawing temperature. An optimum temperature has been found for each type of polyethylene, at which the best drawing behaviour is found. It appears that the temperature range for effective drawing (leading to a high draw ratio and high Young's modulus) depends on the molecular weight and its distribution. The temperature range of the effective drawing is shifted towards higher temperatures for polyethylene exhibiting broader molecular weight distribution and higher weightaverage molecular weight. Ultra-high modulus and transport samples have been obtained by drawing high density polyethylene with broad molecular weight distribution ($\text{M}\text{?}{}_{\mathrm{w}}\text{M}\text{?}{}_{\mathrm{n}}\text{～ 20}$ and $\text{M}\text{?}{}_{\mathrm{w}}\text{～ 200 000}$) at higher drawing temperatures. It has been found that in the range of drawing temperatures 80–105°C the modulus of this polyethylene is higher for samples drawn at higher temperatures. Transparent samples with draw ratios of 35–40 and with Young's moduli of 600–650 kbar (at room temperature) have been obtained by drawing the polyethylene at 100°–105°C. We conclude that the high molecular fraction in the polyethylene, forming tie molecules in the drawn material, is responsible for the high modulus, while the low molecular weight fraction facilitates alignment of the long chains and retards the internal voiding (whitening) to a very high draw ratio during drawing at the higher temperatures.     

Studies of cyclic and linear poly(dimethyl siloxanes): 2. Preparative gel permeation chromatography

A preparative gel permeation chromatographic (g.p.c.) instrument has been constructed and used to separate broad fractions of cyclic poly(dimethyl siloxanes) into sharp fractions with heterogeneity indices $\text{M}\text{?}{}_{\mathrm{w}}\text{M}\text{?}{}_{\mathrm{n}}\text{= 1.05 ± 0.02}$. The number-average molecular weights $\text{M}\text{?}{}_{\mathrm{n}}$ of the cyclic polymer fractions obtained were as high as 50 000, corresponding to number-average numbers of skeletal bonds $\text{n}\text{?}{}_{\mathrm{n}}$ up to 1300. The concentrations of linear poly(dimethyl siloxanes) in all but the highest molecular weight cyclic polymer fractions prepared are believed to be negligible. The preparative g.p.c. instrument was also used to obtain some sharp fractions of linear poly(dimethyl siloxanes).     

Characterization of oligo-poly(dimethylsiloxanes) and their solutions in toluene

A commercial sample of poly(dimethylsiloxane) [PDMS] has been subjected to vacuum distillation, yielding five fractions of $\text{M}\text{?}{}_{\mathrm{n}}$ ranging from 481 to 1132 g mol^?1. These have been characterized at different temperatures with respect to density, refractive index, coefficient of isothermal compressibility, light scattering depolarization ratio and Rayleigh ratio. Similar measurements were made on pure toluene and PDMS/toluene mixtures over the whole composition range for each fraction. For these solutions, linearity in light scattering plots held up to PDMS concentrations of ～0.2 g cm^?3, yielding $\text{M}\text{?}{}_{\mathrm{w}}$ (500–1176 g mol^?1) and large positive values of the second virial coefficient, A₂. In contrast to the findings of others, there was no evidence for association. Data recast in a form in which toluene was regarded as solute and PDMS as solvent gave negative values of A₂. The Mark-Houwink constants for oligomeric PDMS in toluene at 25°C have also been determined. The properties of oligo-PDMS and solutions in toluene are discussed in relation to those of high molecular weight PDMS′     

Dielectric loss of an oligomeric poly(propylene oxide) in the liquid region above Tg

Dynamic dielectric studies of oligomeric poly(propylene oxide) (PPO) of $\text{M}\text{?}{}_{\mathrm{n}}\text{=3034}$, between ?10° and 40°C at 0.1, 1, and 10 KHz, reveal a glass transition and a T >T_g liquid-liquid transition. Analysis of $\text{d}\text{?′}\text{d}\text{T}$ in the liquid region of PPO also indicates the presence of T₁₁. The activation enthalpies for the T_g and T₁₁ transitions have been calculated to be 39 and 18 kCal mol^?1, respectively. The T₁₁ transition in poly(propylene oxide) has been assigned to the motion of the entire polymer molecule.     

Synthesis of electroreactive polymers from poly (m,p-chloromethylstyrene) and copoly (m,p-chloromethylstyrene-styrene)

Polymerization, and copolymerization with styrene, of m,p-chloromethylstyrene have been carried out at 75°C, in chlorobenzene and in the presence of AIBN ($\text{[}\text{AIBN}\text{] ? 6 × 10}{}^{\mathrm{?2}}$, and $\text{12 × 10}{}^{\mathrm{?2}}\text{m}$, respectively). The polymer molecular weights, determined by g.p.c., are: $\text{M}\text{?}{}_{\mathrm{w}}\text{= 8670}$, $\text{M}\text{?}{}_{\mathrm{n}}\text{= 5860}$, and $\text{M}\text{?}{}_{\mathrm{w}}\text{/-M}{}_{\mathrm{n}}\text{= 1.48}$ for the homopolymer, poly(m,p-chloromethylstyrene), (1a); and $\text{M}\text{?}{}_{\mathrm{w}}\text{= 8805}$, $\text{M}\text{?}{}_{\mathrm{n}}\text{= 5144}$, and $\text{M}\text{?}{}_{\mathrm{w}}\text{/-M}{}_{\mathrm{n}}\text{= 1.71}$ for the copolymer, copoly(m,p-chloromethylstyrene-styrene), (2a). A series of phosphine derivatives of both 1a and 2a are prepared by the reaction of the polymers with either chlorodiphenylphosphine/lithium, or diphenylphosphine/potassium tert. butoxide. A number of other potentially electroreactive derivatives of 2a are obtained by reacting the polymer with 2-aminoanthraquinone, 3-N-methylamino-propionitrile, or 2-(2-aminoethyl) pyridine. The phosphinated polymers are reacted with bis-benzonitrilepalladium-(II) chloride to obtain a series of polymer-palladium(II) complexes containing 8.5–12.9% palladium. Similarly, reaction of the last-named bidentate polymeric ligand with cupric acetylacetonate, or cupric sulphate pentahydrate, produces polymer-copper(II) complexes having 5.8, or 3.3% copper, respectively. The inter/intra-chain nature of some of the side reactions during the derivatization of the chloromethylated polymers, and that of the complex formation between transition metal centres and macromolecular ligands, are briefly discussed in view of the experimental results.     

Gas-liquid chromatography study of poly(ethylene oxide)-solvent interactions: estimation of polymer solubility parameter

The thermodynamics of the interactions in the liquid state (70°–150°C) between poly(ethylene oxide) ($\text{M}\text{?}{}_{\mathrm{n}}\text{= 10}{}^4$) and 32 solvents covering a wide range of structure and polarity (from n-hexane to 2,2,2-trifluoroethanol) were studied by gas-liquid chromatography. The regular solution theory, in spite of its well known limitations, does allow a very self-consistent interpretation of all the data for the systems characterized by a positive Flory parameter χ, including systems of poly(ethylene oxide) and a self-associated alcohol where specific hydrogen bonding is well known. The polymer solubility parameter δ₂ (δ₂ = 9.6 ± 0.1 (cal cm^?3)^0.5 at 70°C and its temperature dependence are easily derived with good accuracy.