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Synthesis and Characterization of New Highly Soluble Polyamides Derived from α, α’-Bis[3,5-dimethyl-4-(4-aminophenoxy)phenyl]-1,4-Diisopropylbenzene

The compatibility and crystallization behavior of poly(phenyl acetylene) (PPA) polycaprolactone (PCL) blends were investigated. PPA and PCL were partially miscible in the melt. PCL composition in the PCL-rich phase was calculated from the observed glass transition temperature with the consideration of the perturbation of amorphous phase composition by the crystallization of PCL. PCL composition in PCL-rich phase ranged from ca. 91 wt% to 94 wt%. The melting point of PCL was depressed upon blending. The isothermal crystallization kinetics of the blends was analyzed by Avrami equation. The crystallization rate decreased with increasing PPA composition in the PCL-rich phase. The crystal fold surface free energy σ e of ca. 90 erg cm -2 was obtained from Lauritzen Hoffman analysis considering regime II kinetics. Fold surface free energy was found to increase slightly with PPA composition.

Synthesis and Properties of Polyamides Derived from 2,2-Bis[4-[2-(4-aminophenoxy)-ethoxy]phenyl]propane by Direct Polycondensation

Synthesis and Properties of Polyimides Derived from 1,4-Bis(4-aminophenoxy)-2- tert -butylbenzene

The alternating copolymer of phenylacetylene (PA) and carbon monoxide (CO) (poly(PA-alt-CO)) synthesized by palladium complex has been blended with polystyrene (PS) and poly(e-caprolactone) (PCL). The miscibility of the blends was investigated by differential scanning calorimetry (DSC). A single Tg was observed over the entire composition range for both blending systems, indicating that PS and PCL were miscible with poly(PA-alt-CO). The effect of blending with poly(PA-alt-CO) on the crystallization behavior of PCL was also studied. Both the degree of crystallinity and the crystallization rate of PCL were found to be depressed with the presence of copolymer. Blending with poly(PA-alt-CO) also exerted a strong effect on the melting behavior of PCL. The recrystallization of PCL in the melting region was hindered by poly(PA-alt-CO).

In this work, the authors conducted the terpolymerization of carbon monoxide (CO), styrene (St), and norbornene (NBE) with Pd(CH3COO)2 in CH3OH under various molar ratios of norbornene to styrene at 90°C. Infrared spectra, 1H NMR and 13C NMR analyses confirmed that the NBE/St/CO terpolymers contain ketone, styrene unit, and ring structure of norbornene. Physical and thermal properties of the NBE/St/CO terpolyrners were also investigated by a differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), solubility and X-ray diffraction analyses. The results indicated that glass transition temperature (Tg) of the terpolymers increased when norbornene was introduced. Terpolymer increased molar ratio of norbornene to styrene was found to not only be more thermally stable, but also to increase solubility. As the NBE/St molar ratio became larger than 0.375 in terpolymer, the terpolymers were soluble in chloroform, tetrahydrofuran (THF), methylene chloride, ethyl acetate, benzene, dimethylacetamide (DMAC), and pyridine. X-Ray diffraction results indicated that the terpolymer increased molar ratio of NBE/St in the terpolymer decreased the degree of crystallinity and the angle of maximum intensity owing to the bulky norbornene group. Hydrogenation of NBE/St/CO terpolymer with a reducing agent yielded a hydroxyl-containing polymer.

Carbon monoxide and norbornene (NBE) with Pd(CH 3 COO) 2 under various conditions were copolymerized at 90°C. Elemental analysis, infrared spectra and NMR spectra showed that the copolymers contained ketone and ring structures. Bidentate nitrogen and phosphorus ligands were more effective ligands to stabilize catalytic activity than monodentate arsenic or phosphorus ligands. Methanol and the protonic acid served as coinitiator and chain-transfer agents. X-Ray diffraction analysis shows the copolymer to be partially crystalline. Thermogravimctric analysis showed that the copolymer started to lose mass at 350°C and that maximum decomposition occurred at 447 C. The NBE/CO copolymer obtained from various ligands has a glass transition temperature (T g ) in the range 100-126°C. Hydrogenation of norbornene/CO copolymer with a reducing agent yielded a hydroxy-containing polymer.

Polymerization of phenylacetylene initiated by tungsten carbene complex 4 was investigated in various conditions. The rate of polymerization in polar solvents (such as CH2Cl2) were found to be slower than those in nonpolar solvents (such as n-hexane). The higher the polymerization temperature and the lower the initiator concentration, the higher molar mass was obtained. Kinetic orders, apparent rate constants and thermodynamic parameters were determined. Mechanism for initiation and propagation reactions are proposed based on the experimental results. IR and NMR spectra show predominant characteristic of trans structure in poly(phenylacetylene).

An ESR study on the radical polymerization of methyl methacrylate and its homologs was carried out in frozen aromatic solvents, using benzoyl peroxide as a photosensitizer. A well-resolved 9-line spectrum was observed and its intensity distribution was found to change with temperature and the medium. In order to elucidate the origin of the 9 lines, deuterated methyl methacrylates and triphenylmethyl methacrylate having a bulky ester group were used. A 4-line spectrum (1:3:3:1) was observed for methyl methacrylate-β-d2 (MMA-β-d2). A 3-line spectrum, whose intensity distribution was not binomial, was recorded for methyl-d3 methacrylate (MMA-d3). A 5-line spectrum (1:4:6:4:1) was recorded for triphenylmethyl methacrylate. The temperature dependence of these spectra was also investigated. It was concluded from these results that the two conformations of the propagating radicals are responsible for the 9-line spectrum of methyl methacrylate in glassy aromatic solvents.

The radical polymerization of methyl methacrylate (MMA) in various aromatic solvents was studied under the same conditions as that of phenyl methacrylate (PMA) reported previously. The propagation-rate constants (kp) and termination-rate constants (kt) were determined by intermittent illumination methods. The variation in the kp values for MMA with aromatic solvents had the same trend as that for PMA, although the solvent effect on the former values was somewhat smaller than that on the latter. Variation in kp values with solvents can be explained by the formation of an electron donor–acceptor complex and is correlated with the delocalization stabilization of the complex formation. The dependence of kp value on the monomer concentration supports the view that a propagating radical complexed with a solvent is in the dormant state. A study of temperature dependence on kp and kt values was also carried out in benzene and activation energy of these values determined to be 5.0±0.8 and 0.38±0.10 kcal mol−1, respectively.

Absolute rate constants of vinyl acetate (VAC) polymerization have been measured by using the intermittent illumination method in various aromatic solvents and ethyl acetate at 30°. It was shown that the solvent effect was mainly ascribed to the variation in propagation rate constants (kp) with solvents rather than that in termination rate constants (kt). The kp increased in the order: benzonitrile < ethyl benzoate < anisole < chlorobenzene < fluorobenzene < benzene < ethyl acetate. This order is almost the same as that for vinyl benzoate (VBZ) previously reported. There was about an eightyfold difference between the largest and the smallest values. This large variation in kp is explained neither by copolymerization through solvents nor the chain transfer to solvents, but by a reversible complex formation between the propagating radical and aromatic solvents. The kp was determined in mixed solvents of ethyl benzoate and ethyl acetate, decreasing with increasing content of ethyl benzoate. This result supports the idea of a reversible complex. The stability constants (Ks) of the complex were estimated on the assumption that the complexed radical was in a dormant state and inactive in the polymerization. The correlation between Ks or kp and the calculated delocalization stabilization energy for the complex was found, and supported the explanation for the solvent effect.