Several acrylic esters were polymerized with radical and anionic initiators and the stereoregularity of the polymers was determined. The radical polymerization of tert-butyl acrylate gave syndiotactic-rich polymers at low temperatures as did isopropyl and trimethylsilyl acrylates. A radically obtained polymer of triphenylmethyl acrylate was atactic in contrast to poly(triphenylmethy1 methacrylate). In the anionic polymerization with phenylmagnesium bromide or butyllithium as catalyst, the stereoregularity of the polymers was governed by the coordination of the catalyst which depends on the polarity and bulkiness of ester groups, the polarity of solvents, and the temperature in the polymerization. ZUSAMMENFASSUNG:Die Mikrotaktizitat einiger radikalisch bzw. anionisch hergestellter Polyacrylate wurde bestimmt. Die radikalische Polymerisation von tert-Butylacrylat ergabebenso wie die des Isopropyl-bzw. Trimethylsilylacrylatesbei niedrigen Temperaturen Polymere mit hohem Gehalt an syndiotaktischen Dyaden. Ein radikalisch hergestelltes Poly(triphenylmethylacrylat) war, im Gegensatz zu Poly(triphenylmethyImethacrylat), ataktisch. Bei der anionischen Polymerisation mit Phenylmagnesiumbromid bzw. Butyllithium wird die Mikrotaktizitat des Polymeren von der Koordination des Katalysators bestimmt. Es wurde gefunden, da13 die Art der Koordination abhangt von der Polaritat und Raumerfiillung der Estergruppen, der Polaritat des Losungsmittels sowie von der Reaktionstemperatur. d, 1 M solution in heptane, 0,7 ml. e, 1 M solution in heptane, 2 ml. f, 1 M solution in heptane, 0,6 ml. g, Not determined. h, 2,3 M solution in diethyl ether, 0,3 ml. Dibenzo-18-crown-6, mole ratio [Crown]/[catalyst] = 1.

α‐Methylvinyl methyl ether, ethyl ether, and isobutyl ether were polymerized under various polymerization conditions and the structure of the polymers was determined by 1H‐ and 13C‐NMR spectroscopy. α‐Methyl and β‐methylene carbon spectra of poly(α‐methylvinyl isobutyl ether) showed splitting and were analyzed by triad and tetrad sequences. β‐Methylene carbon spectra of poly(α‐methylvinyl ethyl ether) also showed splitting. When Eu(fod)3 was added, α‐methyl and methoxy proton spectra in benzene of poly(α‐methylvinyl methyl ether) showed splitting assigned to triad tacticities. All the polymers obtained in polar solvents exhibited an increase in syndiotacticity. The polymerization mechanism is discussed.

In polyisocyanurate foam production, alkali metal catalysts of organic carboxylic acids and hydroxyalkyltrimethyl quaternary ammonium salts are traditional standards as polyisocyanurate foam catalysts. The activity of these catalysts, however, is not efficient at low temperature. Therefore, the initiation reactions are extremely delayed, and the flowability of the foam system is far too inferior. In addition, the foam exhibits shrinkage when the thickness of the sprayed layer was thin and the temperature was low while applying the sprayed foams. The combination of other tertiary amine catalysts could improve the flowability; however, the flammability of the foam would be a hazard because the isocyanurate reaction has not fully progressed.For the improvement of the above-mentioned problems, Tosoh Corp. has developed several new quaternary ammonium salt compounds, such as Toyocat-TR20. TR20, however, should be used in conjunction with an alkali 72 Downloaded from metal co-catalyst. Presently, Tosoh has succeeded in developing another new catalyst having even higher catalytic activity at low temperature, which can replace the use of the alkali metal catalyst. The new catalyst provides the low temperature dependency in the isocyanurate reaction activity compared to the traditional isocyanurate catalysts. The new catalyst provides the following advantages:1. The catalytic activity is high. 2. The isocyanurate reaction activity at low temperature is high. 3. The initial foaming reaction is improved, thereby the rise profile is now smooth.In this report, new quaternary ammonium salts will be introduced with comparison data using the FT-IR analytical methods, as well as the evaluation in panel and sprayed foams.

The establishment of CFC-free polyurethane foam systems, aimed at total CFC elimination by the year 1995, is of paramount importance in the present day polyurethane foam technology. Especially in rigid foam systems, the attempts to apply a variety of alternative blowing agents such as HCFC-22, -141b, and -142b, HFC-134a and -356, and hydrocarbons such as n-pentane, isopentane and cyclopentane, as well as all-water blown systems, are being examined. In all cases of alternative blown systems, however, there exist differences in foaming behavior as well as inferior foam properties compared to traditional CFC-11 blown systems. Especially in HCFC-141b and cyclopentane blown systems, which have gained the greatest interest among the above-mentioned options, the following three subjects are of major concern. The requirements involved in achieving the resolution of these problems are dependent not only on the development of major raw materials but also on the selection of suitable auxiliary intermediates such as catalysts and foam stabilizers. (1) Thermal Conductivity; HCFC-141b, cyclopentane and carbon dioxide, which is generated from the reaction of water and isocyanate, have high thermal conductivity compared to CFC-11, thereby causing inferior insulation performance of the foam. Fine cell technology is now being examined in order to improve the thermal conductivity. For the achievement of the fine cell structure, the selection of suitable amine catalyst systems is important, although the effect of foaming stabilizers has an especially large contribution. (2) Dimensional Stability; not only in all-water blown systems, but also in HCFC-141b and cyclopentane blown systems which use water in high concentration, dimensional stability becomes a large problem due to the diffusion of carbon dioxide gas from the foam cell. For the improvement of dimensional stability, there exists the option to increase the foam strength; moreover, it is important to improve the isotropy of cell structure by adjusting amine catalyst systems. (3) Foam density; since 141b and cyclopentane have relatively higher boiling points and less blowing efficiency, lowering the foam density becomes rather difficult. Moreover, lower foam density normally provides poor dimensional stability. It can be said that the catalytic activity ratio in blowing/gelling of amine catalysts play an important role for the lowering of foam density with improved dimensional stability. It is very difficult to improve these three factors simultaneously. In this report, however, the improvements of these subjects are discussed from a standpoint of amine catalysts; also special newly developed nucleation catalyst systems are introduced for cyclopentane and HCFC-141b blown systems.

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