Diol Type Research Articles

Ex-vivo blood compatibility of silicone-containing biomaterials

The acute blood-contacting properties of five silicone-containing elastomers and a poly(vinyl alcohol) coated silicone elastomer were assessed using a canine ex vivo shunt model. The silicone-containing elastomers studied included two thermoset amorphous silica reinforced dimethyl methylvinyl siloxane-based polymers which were extruded as Silastic® RX-50 Medical Grade Tubing (RX-50) and Silastic® Medical Grade Tubing H.P. (HP). They also included three experimental thermoplastic silicone-urea urethane copolymers received as X7-4074 (SP-1), X7-4037 (SP-2), and X7-4943 (SP-3). The RX-50 tubing material showed less thrombus deposition compared to the silicone-urea urethane copolymers. This suggests that the blood-contacting response of a silicone elastomer is strongly affected by the incorporation of the urea urethane segments. Among the silicone-urea urethane copolymers, the SP-3 material showed higher levels of platelet and fibrinogen deposition than the SP-1 and SP-2 materials, whereas the SP-1 and SP-2 samples had similar levels of deposition. These results indicate that the blood-contacting properties of the silicone-urea urethane copolymers were influenced more by the molecular weight of the polydimethylsiloxane than by the type of diol used in the urea urethane segments. The maximal platelet deposition on the poly vinyl alcohol-coated silicone was approximately an order of magnitude greater than those on the silicone-containing elastomers indicating that the PVA coating was more thrombogenic.

Oxidation of Diols with Sodium Bromite Trihydrate in Organic Solvents in the Presence of Alumina

Abstract The title oxidation of diols with two primary hydroxy groups (symmetrical diols) and those with both a primary and a secondary hydroxy group (unsymmetrical diols) gives the corresponding lactones or the hydroxy ketones, being dependent upon the types of diols.

Synthesis and Thermal Properties of Thermotropic Block Copolyetheresters

Various block copolyetheresters with hard segment of poly(alkylene p,p′-bibenzoate) and soft segment of poly(tetramethylene ether) were prepared by melt polycondensation of dimethyl-p,p′-bibenzoate, an alkylene, diol, and a poly(tetramethylene ether) glycol (PTMEG) in the presence of tetrabutyl orthotitanate as catalyst. Their thermal properties were investigated by DSC. The melting temperature of the polyether segment was found to be about 17°C, thus the polyether segment was amorphous above room temperature. The thermal properties of poly(alkylene p,p′-bibenzoate) segment above room temperature were found to be dependent on both the type of alkylene diol and the sequence length of poly(alkylene p,p′-bibenzoate) segment. Theremotropic liquid crystalline behavior was found for some block copolyetheresters and originated from the hard segment.

Antiandrogenic A-homo-B,19-dinor-analogues of androgens from 6β-chloro-5-methyl-19-nor-5β-androst-9-enes

6β-Chloro derivatives of 5-methyl-19-nor-5β-androst-9-enes (Westphalen diol type) with oxygen functionalities in positions 3 and 17 were converted into diene VI by treatment with lithium aluminium hydride. The lipophilic product of hydrogenation of VI was shown to be 4aα-methyl-A-homo-B,19-dinor-5β,10α-androstane-3β,17β-diol (IX). Various paths leading to dihydrotestosteron analogues, e.g. selective acylation or oxidation of diol IX and partial hydrolysis of diacetate X, have been realized. 17β-Hydroxy-4aα-methyl-A-homo-B,19-dinor-5β,10α-androstan-3-one (XVI) has been found to exhibit antiandrogenic activity.

GPC and structural analysis of polyurethane degradation

Linear polyurethane (PUR) prepolymers were synthesized starting from diphenylmethane-4,4′-diisocyanate (MDI) and polyester diol oligomers. Two different types of polyester diols were used: poly(ethylene adipate) (PEA) and poly(ethylene/butylene adipate) (PEBA). The effects of UV irradiation on the photooxidative degradation of prepared PUR prepolymer were studied. The changes in the chain lengths and their distribution as well as the changes in chemical structure were followed. The GPC results show that the photooxidative decomposition is followed by a decrease in molecular mass together with an increase in polydispersity. This indicates a very inhomogeneous degradation, which is a consequence of the specific course and of the intensity of photooxidative degradation. This was confirmed by means of comparative IR and NMR measurements. Conclusions on the difference in behaviour of the two different types of polyester diols used in PUR synthesis were discussed.

Determination of end groups as a function of molecular size for aliphatic polyesters by derivatization of end groups and size-exclusion chromatography with infrared detection

End groups of poly(ethyleneglycol sebacate) having number average molecular weights less than 2500 were characterized as a function of molecular size by derivatizing end groups separately to form 3,5-dinitrobenzoyl and p-nitrobenzyl esters. A hydroxyl end group was reacted with 3,5-dinitrobenzoyl chloride (DNBC) and a carboxyl end group was reacted with O-( p-nitrobenzyl)- N,N′-diisopropyl isourea (PNBD). After separation of these derivatized polyesters by size-exclusion chromatography, the effluent was monitored by using a highly sensitive infrared detector. Concentrations of polyesters were monitored at 1740 cm −1 for a carbonyl group in the main chain, polyesters derivatized with DNBC at 1560 cm −1 for a hydroxyl end group (characteristic absorption band for the nitro group of DNBC), and polyesters derivatized with PNDB at 1537 cm − for a carboxyl end group (a characteristic absorption band for the nitro group of PNBD). By this technique, three types of polyesters having different end groups were characterized: a diol-type polyester, a mixture of polyesters of a diol type and a mono-ol/monocarboxyl type, and a mixture of polyesters of a dicarboxyl type a mono-ol/monocarboxyl type.

Structure‐property relationships in thermoplastic elastomers: I. Segmented polyether‐polyurethanes

AbstractSegmented poly(ether‐b‐urethanes) have been synthesized with 2000 MW polypropylene oxide coupled with diisocyanates and diol type chain extenders. The diisocyanates used were symmetric rigid 4, 4′‐diphenylmethane diisocyanate (MDI), linear aliphatic hexamethylene diisocyanate (HDI), and unsymmetric rigid toluene‐2, 4‐diisocyanate (TDI). The chain extenders were symmetric N, N′‐bis(2‐hydroxyethyl) terephthalamide (BT) and N, N′‐bis(2‐hydroxyethyl)‐hydroquinone (BH) unsymmetric N, N′‐bis(2‐hydroxyethyl)isophthalamide, and linear aliphatic 1, 4‐butanediol (B). Hard segment contents ranged from 20 to 40 wt percent. The thermal behavior of these materials is consistent with phase separation into separate hard and soft domains, In order of increasing temperature above the soft segment Tg, there are transitions which occur in the regions −56 to −36°C (Ta), 70 to 90°C (Tb), and 138 to 168°C (Tm). The former is probably associated with soft segment change from a viscoelastic to an elastomeric state. Values of Ta are ∼ −51 C and −56°C for the MDI‐BT and HDI‐BT polymers, respectively, and are independent of hard segment content. Microscopy showed that the former polymers have spherulitic morphology, so these materials have good microphase separation and exhibit crosslinked elastomeric properties. The TDI‐BT or BI and MDI‐B polyurethane have composition‐independent Ta values of −41 and −36°C, respectively. These materials probably have considerable “domain‐bound‐ary‐mixing”. At low hard segment content the MDI‐B polymers behave as non‐crosslinked elastomers. Only the MDI‐BI polymers have Ta values, which are strongly affected by composition, increasing in magnitude with increasing of hard segment content. This is interpreted as significant “mixing‐in‐domains” and is supported by morphology observed by microscopy. The next higher transition, Tb, probably involves dissociation of interdomain hydrogen bonding. In the case of the MDI‐BT polyurethanes, the spherulites associated with the hard domains had disappeared at 141°C and the few small spherulites in the MDI‐BI polymers disappeared at 130°C. The Tb values are 70, 83 to 90, and 100°C for the MDI‐B, HDI‐BT, and HDI‐BI polymers, respectively. The melting transitions occurred between 138 to 168°C for the various polyurethanes except for the MDI‐BT systems which decompose before melting. Thermal decomposition is a two‐stage process. Hard segments decompose between 200 and 300°C. The initial decomposition temperatures are lowered in the presence of strong acid. Soft segments decompose at higher temperatures. The mechanical properties of the MDI‐BI polyurethanes are charateristic of crosslinked elastomer, the results of which will be presented in a subsequent paper.

Photolysis of the azide group of linear polyester containing 3-azido- o-phthalic groups

This paper presents the results of a study on the photolysis of the azide group in polyesters of 3-azido-ortho-phthalic acid and linear diols. It was stated that the apparent quantum yield of the azide group photolysis depends on the number of carbons separating the azide group and on the diol type, being different for diols with even and odd numbers of carbons. The formulated kinetic equation takes into account the effect of the initial concentration of the azide group on the rate of photolysis. Investigation of all the polyesters with a constant initial concentration of azide groups showed that the number of carbons in a diol does not affect the real quantum yield. However, it is affected by whether that number is odd or even. A value for the activation energy of photolysis was also determined. It amounts to E a = 1·6 kcal mol −1 for polyesters with an odd number of carbons in the diol, and E a = 0·34 kcal mol −1 for polyesters with an even number of carbons in the diol. It can be concluded from the research that the way of introducing the light-sensitive group into the polymer chain is decisive for the primary processes in the polymer under irradiation. The real quantum yield for the light-sensitive group attached to the main chain amounts to φ = 0·61. For the light-sensitive group introduced into the polymer chain this value is smaller; for polymers with an even number of carbons in the diol φ = 0·42−0·47 and for polymers with an odd number of carbons in the diol φ = 0·51−0·54.

Preparation of affinity adsorbents with toyopearl gels

The optimal conditions for the activation of Toyopearl by epichlorohydrin and subsequent immobilization of ligands were investigated. The optimal conditions for the activation were very different from those for agarose gel. The concentration of epoxy groups introduced was as high as 330 μmole per gram of wet gel for Toyopearl HW-55 and 150 μmole per gram of wet gel for Toyopearl HW-65 (diol type). Epoxy-activated Toyopearl was converted into amino and carboxyl derivatives and was subsequently coupled with various ligands. Glycamyl Toyopearl was prepared in a much shorter time (6 h) than agarose gel (800 h), because a higher reaction temperature could be used. The adsorbents obtained were successfully used for the affinity chromatography of lectin and trypsin. However, their adsorption capacities were lower than those of the agarose adsorbents prepared by the same methods.

EXPERIMENTAL EVALUATION OF THE TRANS FRACTION IN CH<sub>2</sub>-CH<sub>2</sub> BONDS OF MELT-QUENCHED POLY (ETHYLENE TEREPHTHALATE)

In a previous paper we speculated that the molecular conformation of poly (ethylene terephthalate) (PET) quenched from the melt is not in random coil state but in frozen metastable state which is easily transformed into the stable crystalline state. This speculation should be confirmed with direct structural evidences. However, experimental methods to investigate the structure of melt-quenched PET are scarce. In this paper we have evaluated the trans fraction in CH2-CH2 bonds of PET quenched from the melt by means of infrared spectroscopy.The trans fraction was determined by two methods. The first one uses the ratio of intensities of the annealed sample and the melt-quenched one for both the trans and gauche bands (At/A°t and Ag/A°g). The trans fraction of melt-quenched PET (X°t) can be obtained from the following equation; where Ft and Fg are the ratio of extinction coefficient of the annealed sample and that of the meltquenched one for trans and gauche chain respectively. These are assumed to be unity. Scbonherr used the peak heights as the absorbance values and the 1578 cm-1 band as the internal thickness band. However, our study shows that the band widths change upon annealing and the 1578 cm-1 band is a crystallization sensitive band. In order to obtain reasonable value of the trans fraction, we used the integrated intensities as the absorbance values and the 1505 cm-1 band as the internal thickness band. Namely, a computer program was written which resolves the infrared spectar in the 760-930 cm-1 region of PET into composite vibrational bands whose envelopes are assumed to be Lorenzian. The computation was based on the principle of least squares. The integrated absorption intensity for the individual band was accurately obtained. By these procedures, we evaluated 0.2 as the value of trans fraction in melt-quenched PET.The second one is newly proposed here. If one obtains the ratio of extinction coefficient of the trans and the gauche band (et /eg ), the trans fraction (X°t) can be evaluated from the following equation; where A°t and A°g are the absorbances for the trans and gauche band in melt-quenched PET. The ratio of extinction coefficient of the trans and the gauche band was determined by using intensities of the trans and the gauche band in crystals of diol type oligomers of PET in which the CH2-CH2 bonds in both molecular ends were found to be gauche. The result was consistent with that from the improved Schonherr's method. Thus, a considerably small value of 0.2 is conclusively assigned to the trans fraction in CH2-CH2 bonds of melt-quenched PET.

The functionality of polyoxypropylene polyols

The results of the fractionation and the mol.wt. of polyoxypropylene polyols (POPP) produced by the polyaddition reaction of propylene oxide with potassium glycerate in glycerol have shown that the neutral polyether contains two diol types one of which is the product of water and propylene oxide, the other from hydrolysis of the cis-propylene groups in the mono-ol. The amount of the second diol type produced is equivalent to the cis-propylene groups content of the alkaline poly-ether. The OH-groups content of the neutral poly-ether equals the sum of the OH-groups present in the glycerol, water, allyl alcohol and from the cis-propenyl groups present in the alkaline polymer. This has qualitatively confirmed the mechanism of the chain transfer on the monomer during the anionic polymerization of the propylene oxide and has shown this reaction to be the only source of new OH-groups production during the polymerization.

Some Constituents of Casearia ilicifolia Vent

In the leaves of Casearia ilicifolia (Flacourtiaceae) N–alkanes, 24–methylene–cycloartanol, cycloartenol and β–sitosterol have been identified and determined quantitatively. The alcoholic extract showed the presence of the flavonoids apigenin, kaempferol, quercetin and condensed tannins of the flavan–3, 4–diol type.

Reaction of α, 6omega;-Diol Type Oligomers with Triphenylmethane- 4, 4', 4"-triyltriisocyanate

ポリエチレングリコール(PEG)およびα,ω-ジオール型ブタジエンオリゴマー(PBd)とトリフェ=ルメタン-4,4,4"-トリイル=トリイソシアナート(TTI)との反応を速度論的に解析した。 TTI中の三つのイソシアナート基の反応性は反応の進行にともないイソシアナート基がウレタン基に置換されることによりいちじるしく低下することが大過剃のn-ブタノールとの反応から確認された。反応初期の二次速度定数秘はTTIとPEGとの反応では通常のウレタン化反応と同様に水酸基,イソシアナート基初濃度に依存しないが,PBdとの反応ではイソシアナート基初濃度の増加とともに増大する。低分子アルコールとしてエチルセルソルブとn-ブタノールを用いた反応では前者はPEG,後者はPBdと同様の挙動を示し,TTIとアルコールとの反応の機構はアルコール種により異なる PBdおよびn-ブタノールとの反応ではイソシアナート2分子によるコンプレヅクスあるいはイソシアナート2分子とアルコールとの三元系ゴンプレックスの形成を素反応として考慮する必要がある。ただし,水酸基大過剰の場合にはkaはイソシアナト基初濃度に依存せず,水酸基とイソシアナート基によるコンプレックス形成とイソシアナート2分子によるコンプレヅクスまたは三元系コンプレックスの形成が競争的に生起していることが示唆された

On the analysis of long-chain alkane diols and glycerol ethers in biochemical studies

The chromatographic behavior of 1,2-, 1,3-, 1,4-, and 1,12-long-chain alkane diols and 1-O-alkylglycerols and their derivatives has been compared. Thin-layer chromatography on Silica Gel G gives poor separations of the 1,2-, 1,3-, and 1,4-alkane diols, O-alkylglycerols, and some of their isopropylidene derivatives. However, gas-liquid chromatography on 10% EGSS-X (coated on 100-120 mesh Gas-Chrom P) resolves the isopropylidenes of the alkane diols and O-alkylglycerols. We also document the formation of 1,3-alkane diols (after LiAlH(4) reduction) from 1-(14)C-labeled fatty acids incubated with mitochondrial fractions from heart and liver of rats. The labeled 1,3-alkane diol was identified by gas-liquid chromatography of its isopropylidene derivative and by its behavior after periodate oxidation. These results serve to caution investigators in the glycerol ether field against incorrect interpretation of data obtained on the incorporation of labeled fatty acids into alkyl ether bonds of glycerolipids. The methodology described points out a technique for distinguishing several types of alkane diols from O-alkylglycerols.