Chuzo Kato

Evidence for the formation of interlayer polyacrylonitrile in kaolinite

A kaolinite-polymer intercalation complex was apparently formed for the first time by the polymerization of acrylonitrile between the kaolinite layers. A kaolinite-ammonium acetate intercalation complex was dispersed in acrylonitrile monomer. The monomer was apparently incorporated between the layers by displacing intercalated ammonium acetate. After the removal of excess monomer, the intercalation complex was heated to cause polymerization. The resulting kaolinite-polyacrylonitrile (PAN) intercalate showed a basal spacing of ∼ 13–14 Å. On heating the complex at 220°C for 1 hr in air, the spacing decreased slightly. The hydrogen bond between the hydroxyls of kaolinite and probably the C≡N group of PAN was not affected after heating at 220°C. Even after heating at 400°C, the layers expanded. Because the starting kaolinite-ammonium acetate intercalation complex decomposed at a much lower temperature, these observations strongly suggest the presence of PAN between the layers.

Solid-state intercalation of naphthalene and anthracene into alkylammonium-montmorillonites

Intercalation of naphthalene and anthracene into alkyltrimethylammonium (CnH2n+1(CH3)3N+; n = 8, 12, 14, 16, and 18)-montmorillonites was carried out by novel solid-solid reactions at room temperature. Octyltrimethylammonium(C8)-montmorillonite did not form an intercalation compound with either naphthalene or anthracene. Naphthalene was intercalated into both dodecyltrimethylammonium(C12)- and octadecyltrimethylammonium(C18)-montmorillonites to give intercalation compounds. On the other hand, the solid-solid reaction between dodecyltrimethylammonium(C12)- or tetradecyltrimethylammonium(C14)-montmorillonite and anthracene gave only partly intercalated compounds while hexadecyltrimethylammonium(C16)- and octadecyltrimethylammonium(C18)-montmorillonites gave single phase intercalation compounds. The hydrophobic interactions between alkylammonium-montmorillonites and the aromatic compounds are thought to be the driving force for the solid-state intercalation. The extent of the increase in the basal spacing may also be involved in the different reactivity.

PREPARATION AND ELECTRICAL PROPERTIES OF QUATERNARY AMMONIUM MONTMORILLONITE-POLYSTYRENE COMPLEXES

Intercalation compounds of styrene and quaternary ammonium montmorillonite were prepared by immersion of the clay in styrene monomer. The intercalation of stearyltrimethylammonium (CH3(CH2)17N(CH3)3+)-montmorillonite and styrene showed an expansion of the basal spacing to a constant value of ∼32 Å after immersion for 10 days. After polymerization, the amount of polystyrene in the interlayer region was determined by thermal gravimetric analysis. Styrene adsorption initially increased with increasing quaternary ammonium cation and then became approximately constant when loading of the quaternary ammonium cation exceeded 100 meq/100 g clay. The volume resistivity of the stearyltrimethylammonium-montmorilionite-polystyrene complex, which was determined with a high resistance meter, was greater than that of both the quaternary ammonium-montmorillonite and the montmorillonite, and increased in proportion to the amount of polymer adsorbed. These data indicate that polystyrene improved the insulating properties of the clay films.РезюмеПрослойки старена и четвертачно/аммоний-монтмориллонита были приготовлены путем иммерсии глины в мономере стирена. Прослойки стеарилтриметиламмоний (СН3(СН2)17N(СН3)з+)-монтмориллонита и стирена после иммерсии в течение 10 дней показали расширение основных промежутков до постоянной величины ~32 Å. После полимеризации количество полистирена в межслойной области определялось путём термогравиметрического анализа. Сначала адсорбция стирена увеличивалась вместе с увеличивающимся количеством четвертичного катиона аммония и оставалась приблизительно неизменной, когда количество этого катиона превышало 100 мэкв/100 г глины. Объёмное удельное сопротивление комплекса стеарилтриметиламмоний-монтмориллонит-полистирен, определенное при помощи прибора высокого сопротивления, было больше, чем для четвертично-аммоний-монтмориллонита и монтмориллонита, и оно увеличивалось пропорционально количеству адсорбированного полимера. Эти данные указывают но то, что полистирен улучшил изоляционные свойства глинистых фильмов. [Е.С.]ResümeeEinlagerungsverbindungen von Styrol und quarternärem Ammonium-Montmorillonit wurden mittels Immersion von Ton in monomerem Styrol hergestellt. Die Einlagerung von Styrol in Stearyltrimethylammonium (CH3(CH2)l7N(CH3)3+)-Montmorillonit führt nach einer Immersion von 10 Tagen zu einer Aufweitung des Basisabstandes auf einen konstanten Wert von etwa 32 Å. Nach der Polymerisation wurde der Gehalt an Polystyrol in den Zwischenschichten mittels thermogravimetrischer Analyse bestimmt. Die Styrol-Adsorption nahm zu Beginn mit zunehmenden quarternären Ammonium-Kationen zu und wurde dann, wenn die Beladung mit den quartern:aren Kationen 100 mÄqu/100 g Ton überschritten hat, annähernd konstant. Der Gesamtwiderstand des Stearyltrimethylammonium-Montmorillonit-Polystyrol-Komplexes, der mit einem hochohmigen Meßgerät bestimmt wurde, war größer als der des quarternären Ammonium-Montmorillonit und der des Montmorillonites und nahm mit der Menge des adsorbierten Polymers zu. Diese Daten deuten darauf hin, daß das Polystyrol die Isoliereigenschaften der Tonfilme verbesserte. [U.W.]RésuméLes composés d’intercalation de styrène et de montmorillonite ammonium quaternaire ont été préparés par immersion de l’argile dans le monomère styrène. L’intercalation de montmorillonite stéaryltrimethylammonium (CH3(CH2)17N(CH3)3+) et de styrène a montré une expansion de l’espacement de base à une valeur constante de 32 Å après immersion pendant 10jours. Après la polymérisation, la quantité de polystyrène dans la région intercouche a été déterminée par analyse gravimétrique thermale. L’adsorption de styrène a initialement augmenté proportionellement à l’accroissement du cation ammonium, et est ensuite devenu à peu près constante lorsque le chargement du cation ammonium quaternaire excédait 100 meq/100 g d’argile. La résistivité de volume du complexe stéaryltrimethylammonium-montmorillonite polystyrène, determinée par un compteur à haute résistance, était plus élevée que celle de la montmorillonite-ammonium quaternaire, ainsi que de la montmorillonite, et angmentait proportionellement à la quantité de polymère adsorbée. Ces données indiquent que la polystyrène a amelioré les proprietés isolantes des films d’argile. [D.J.]

Organic derivatives of layered polysilicates: I. Trimethylsilylation of magadiite and kenyaite

Organic derivatization of layered polysilicates (magadiite Na2Si14O29·xH2O and kenyaite K2Si20O41·xH2O) was performed by reaction of the tetraalkylammonium polysilicate intercalation compounds with chlorotrimethylsilane ((CH3)3SiCl) as the silylating agent. The formation of the organic derivatives was confirmed by X-ray powder diffraction, IR, 29Si MAS NMR, and elemental analysis, and revealed the bonding between the trimethylsilyl groups and the interlayer silanol groups. The advantage of using tetraalkylammonium polysilicate intercalation compounds as intermediates for organic derivatization is elucidated.

Preparation of a kaolinite-polyacrylamide intercalation compound

Acrylamide has been polymerized between the layers of kaolinite by heat treatment. Acrylamide monomer was first intercalated by the displacement reaction between a kaolinite-N-methylformamide (NMF) intercalation compound and a 10% acrylamide aqueous solution. The resulting intercalation compound showed a basal spacing of 11.3 Å. Infrared (IR) spectroscopy and 13C nuclear magnetic resonance spectroscopy with cross polarization and magic angle spinning (13C CP/MAS-NMR) indicated the replacement of NMF by acrylamide. IR spectroscopy also showed the formation of hydrogen bonds with the hydroxyls of kaolinite. When the kaolinite-acrylamide intercalation compound was heated at 300°C for 1 hr, the basal spacing increased to 11.4 Å, and IR and 13C CP/MAS-NMR showed the disappearance of C=C bonds, indicating the polymerization of acrylamide. The heat-treated kaolinite-acrylamide intercalation compound was resistant to 30 min-washing with water, whereas the untreated kaolinite-acrylamide intercalation compound collapsed after the same treatment, an observation consistent with acrylamide polymerization between the layers of kaolinite. IR spectroscopy revealed that Polyacrylamide was hydrogen bonded to kaolinite, but in a manner different from the hydrogen bonding of acrylamide.

Solid-state intercalation of acrylamide into smectites and Na-taeniolite

Abstract Various clay minerals of the smectite group could form intercalation compounds with acrylamide by solid-solid reaction at room temperature and within a few minutes of contacting the reactants. Taeniolite, a synthetic fluor-mica with a higher layer charge density than smectites, gave an only incomplete intercalation. The propensity of the minerals for intercalating acrylamide was correlated with their reactivity towards ethylene glycol. Because of their rapidity and simplicity, solid-solid reactions provide a new way of introducing organic species into the interlayer spaces of smectites.

AlN formation from a hydrotalcite-polyacrylonitrile intercalation compound by carbothermal reduction

Abstract As a precursor for AlN production by carbothermal reduction, a hydrotalcite (layered magnesium-aluminum double hydroxide)-polyacrylonitrile (PAN) intercalation compound has been prepared for the first time. After the layers were expanded by the replacement of the interlayer anions with the CH 3 (CH 2 ) 11 OSO 3 − ions, the acrylonitrile monomer was intercalated and subsequently polymerized. By the heat treatments at 1100°C–1600°C in N 2 , AlN, MgO and MgS formed. MgO was detected in the products heated up to 1300°C. MgS formation was observed in the reactions below 1500°C. On heating at 1600°C, single phase submicron AlN grains were obtained.

Synthesis of montmorillonite-viologen intercalation compounds and their photochromic behaviour

The photochemical properties of four different viologen di-cations (V2+,1,1′-dipropyl-, 1,1′-diheptyl-, 1,1′-diphenylmethyl- and 1,1′-diphenylethyl-4,4′-bipyridinium di-cations) intercalated into the interlayer space of montmorillonite have been studied. The colour of the intercalation compounds which were co-intercalated by poly(vinyl pyrrolidone)(PVP) changed to blue when irradiated by a mercury lamp, showing the formation of the radical cations. Their characteristic absorptions appeared at ca. 610 and 400 nm in their visible spectra. Since the viologens were present in their cationic forms in the interlayer space it was thought that PVP acted as an electron donor for the photochemical reduction of the viologens. The intensity decay of the radical cations was very slow in comparison with the species in PVP matrices, indicating their remarkable stability.

Oriented microporous film of tetramethylammonium pillared saponite

Tetramethylammonium saponite film has been prepared and its structure has been characterized. By casting the aqueous suspension of the tetramethylammonium–saponite, a transparent film was obtained. The film is composed of oriented silicate particles with ab planes parallel to the substrate. The interlayer tetramethylammonium ions provide micropores in the interlayer space and the micropores are interconnected in the direction parallel to the silicate sheet. The film is regarded as a unique immobilizing medium for photoactive species because of the transparency and the anisotropic microporous structure.

PREPARATION OF MONTMORILLONITE-NYLON COMPLEXES AND THEIR THERMAL PROPERTIES

Montmorillonite-aminocaproic acid complexes (monomer complexes) were prepared by the intercalation of 6-aminocaproic acid to various homoionic (Na+, Ca2+, Mg2+, Co2+, and Cu2+) montmorillonites. Infrared spectra of the monomer complexes indicated that the interaction between the exchangeable cations and the 6-aminocaproic acid increased in the following order: Na-, Ca-, and Mg- < Co- < Cu-montmorillonite-aminocaproic acid complex. Montmorillonite-nylon complexes (polymer complexes) were prepared by thermal treatment of the monomer complexes, which was confirmed by X-ray powder diffraction and infrared spectroscopy the results of which indicated the condensation of 6-aminocaproic acid in the interlayer space.Thermal degradation of montmorillonite-nylon complexes was studied by thermogravimetry. It was found that the thermal stability of the polymer complexes increased in the following order: Cu- < Co- < Na- < Mg- < Ca-montmorillonite-nylon complex.It was suggested that the difference in thermal stability depended upon the length of the polymer chain which might be influenced by the interaction between the exchangeable cations and the 6-aminocaproic acid. The activation energy for the thermal degradation of each montmorillonite-nylon complex was obtained, and the value for Cu-montmorillonite-nylon complex was smaller than that for the other cation-exchanged montmorillonite-nylon complexes.РезюмеКомплексы монтмориллонит-аминокапроновая кислота (мономерные комплексы) были приготовлены интеркалацией 6-аминокапроновой кислоты в различные гомоионные (Na+, Са2+, Mg2+, Со2+, и Си2+-) монтмориллониты. Инфракрасные спектры мономерных комплексов указывали, что взаимодействие между обменными катионами и 6-аминокапроновой кислотой возрастает в следующем порядке: Na-, Са-, и Mg- <Со- <Си-монтмориллонит-аминокапроновый кислотный комплекс. Комплексы монтмориллонит-нейлон (полимерные комплексы) приготавливались термальной обработкой мономерных комплексов, наличие которых подтверждалось порошковым методом рентгеноструктурного анализа и инфракрасной спектроскопией, которые указывали на конденсацию 6-аминокапроновой кислоты в межслойных промежутках.Термальная деградация комплексов монтмориллонит-нейлон изучалась с помощью термогравиметрии. Было обнаружено, что термальная стабильность полимерных комплексов возрастает в следующем порядке: Си- <Со- <Na- <Mg- <Са-монтмориллонит-нейлоновый комплекс.Предполагается, что различие в термальной стабильности зависит от длины полимерной цепи, на которую должно влиять взаимодействие обменных катионов и 6-аминокапроновой кислоты. Была получена активационная энергия для термальной деградаций каждого комплекса монтмориллонит-нейлон, и ее значение для комплекса Cu-монтмориллонит-нейлон оказалось меньше, чем для других катионно-обменных комплексов монтмориллонит-нейлон.ResümeeMontmorillonit-Aminocapronsäure Komplexe (monomere Komplexe) wurden durch die Interkalation von 6-Aminocapronsäure in verschiedene homoionische (Na+, Ca2+, Mg2+, Co2+, und Cu2+) Montmorilloniten hergestellt. Infrarotspektren der monomerischen Komplexe deuteten an, daß der Einfluß, den die austauschbaren Kationen und die 6-Aminocapronsäure aufeinander haben, in der folgenden Richtung zunimmt: Na-, Ca-, und Mg- <Co- <Cu-Montomrillonit-Aminocapronsäurekomplex. Montmorillonit-Nylonkomplexe (polymere Komplexe) wurden durch die thermische Behandlung der monomeren Komplexe präpariert, was durch Röntgenpulverdiagramme und Infrarotspektroskopie, welche die Kondensation von 6-Aminocapronsäure in den Zwischenschichträumen andeuten, bestätigt wurde. Thermische Degradation von Montmorillonit-Nylonkomplexen wurde mittles Thermo- gravimetrie untersucht. Es wurde gefunden, daß die thermische Stabilität der polymeren Komplexe folgendermaßen zunimmt: Cu- <Co- <Na- <Mg- <Ca-Montmorillonit-Nylonkomplex. Es wurde vorgeschlagen, daß der Unterschied in den thermischen Stabilitäten von der Länge der polymeren Kette abhängt, welche durch die Einwirkung der austauschbaren Kationen auf die 6-Aminocapron- säure beeinflußt sein könnte. Die Aktivierungsenergie für die thermische Degradation für jeden Montmorillonit-Nylonkomplex wurde erhalten; der Wert für den Cu-Montmorillonit-Nylonkomplex war niedriger als für die anderen Kation-Montmorillonit-Nylonkomplexe.RésuméDes complexes montmorillonite-acide aminocaproique (complexes monomères) ont été préparés par intercalation d’acide aminocaproique-6 à diverses montmorillonites (Na+, Ca2+, Mg2+, Co2+, et Cu2+) homoioniques. Les spectres infrarouges des complexes monomères ont indiqué que l’action entre les cations échangeables et l’acide aminocaproique-6, croît dans l’ordre suivant; le complexe acide aminocaproique-montmorillonite-Na, Ca, Mg <-Co <-Cu. Les complexes montmorillonites-nylon (complexes polymères) ont été préparés par traitement thermique de complexes monomères, ce qui a été confirmé au moyen de la diffraction aux rayons-X et la spectroscopie infrarouge dont les résultats ont indiqué la condensation de l’acide aminocaproique-6 dans l’espace interfeuillet. La dégradation thermique des complexes montmorillonite-nylon a été étudiée par thermogravimétrie. On a trouvé que la stabilité thermique des complexes polymères croît dans l’ordre suivant; les complexes nylon-montmorillonite- Cu <-Co <-Na <-Mg <-Ca. Il a été suggéré que la différence de stabilité thermique dépendait de la longueur de la chaîne polymère qui pourrait être influencée par l’interaction entre les cations échangeables et l’acide aminocaproique-6. L’énergie d’activation pour la dégradation thermique de chaque complexe nylon-montmorillonite a été obtenue et la valeur du complexe nylon-montmorillonite-Cu était plus petite que celles des complexes nylon-montmorillonite à cations échangés.