Synthesis and properties of poly(tetramethylene terephthalate-co-ethylene terephthalate)–poly(tetramethylene ether) segmented copolymers

A series of polyether–copolyester segmented copolymers ((PBT–PET)PTMG) based on hard segments of tetramethylene terephthalate–ethylene terephthalate copolyester (PBT–PET) and soft segments of poly(tetramethylene ether)(PTMG) was synthesized. The hard : soft segment weight ratio was 30 : 70 and the mole ratio of PBT : PET was 1 : 10; 1 : 6; 1 : 1; 3 : 1, respectively. Their mechanical properties, morphology, crystallization behavior and optical transparency were investigated and compared with poly(tetramethylene terephthalate)–poly(tetramethylene ether)(PBT–PTMG), as well as with poly(ethylene terephthalate)–poly(tetramethylene ether)(PET–PTMG), consisting of the equivalent composition ratio of hard and soft segments. It was found that the transparency could be improved by introducing a small amount of PBT into PET–PTMG through copolymerization. However, a decrease was observed in the transparency if more PBT was added. This is due to the fact that the copolymerization makes both crystallinity and crystallization rate decrease.     

1,2-Cycloaddition of Haloalkenes to Conjugated Fatty Esters

We have studied the reaction of 1,1-dichloro-2,2-difluoro-, chlorotrifluoro-, and tetrafluoro-ethylenes and also hexafluoropropylene withcis,trans andtrans,trans isomers of conjugated methyl octadecadienoate. Reactions gave 50-82% yields of cycloaddition products. The pre-ponderance of products with a cyclobutane struc-ture and a double bonda,β to the cyclobutane ring was shown by IR and NMR spectra. Reactions were carried out in diluent with hy-droquinone inhibitor at autogenous pressure and a temperature of 200C for 5 hr. The distilled adducts are colorless liquids with viscosities rang-ing from 11 to 19 centistokes at 100F. These products and their hydrogenated derivatives ex-hibit low pour points (down to -76F) and may be useful as low-temperature plasticizers or lubricant additives. Presented at AOCS Meeting, Cincinnati, October 1965. N. Utiliz. Ees. and Dev. Div., ARS, USDA.     

Preparation and anti-fouling property of carboxybetaine-based zwitterionic PVDF membrane

This work describes the synthesis and anti-fouling properties of poly(vinylidene fluoride) membrane, grafted with carboxybetaine-based zwitterions. An amphiphilic copolymer, poly(vinylidene fluoride)-graft- poly(N,N-dimethylamino-2-ethylmethacrylate) (PVDF-g-PDMAEMA), was synthesized by radical graft copolymerization, followed by casting the copolymer into a flat membrane, by an immersed phase inversion method. PVDF-g-PDMAEMA membrane was reacted with sodium chloroacetate (SCA) to yield a carboxybetaine-based zwitterionic surface. The membrane showed significantly enhanced hydrophilicity, due to the hydration ability of carboxybetaine-based zwitterions, which inhibited protein adsorption. Compared to pristine PVDF-g-PDMAEMA membrane, carboxybetaine-based zwitterionic membrane exhibited a higher flux recovery in the cyclic filtration.     

Zwitterionic phthalocyanine zinc (II) synthesis,and photodynamic activity comparison with nonionic and cationic phthalocyanine

Zwitterionic structures were helpful for solubility, cellular uptake and activity for many drugs. But few researches about the influence of zwitterionic structures on phthalocyanine were reported. So, in this work, we design and synthesis a zwitterionic zinc (II) phthalocyanines(ZnPcs). And its solubility, photochemical and photodynamic activity to cancer cells was investigated. Furthermore, these properties of other two ZnPcs, nonionic and cationic ZnPcs with same major structure, were also researched simultaneously. Comparative studies indicated that the zwitterions structures could improve the solubility of ZnPc but greatly reduced its reactive oxygen species (ROSs) generation ability and anti-cancer activity in vitro to nonionic and cationic ZnPcs.     

Effects of catalyst on sequence distribution and transparency of poly(tetramethylene terephthalate)–poly(tetramethylene ether) segmented copolymers

Polyether-polyester segmented copolymer based on hard segments of tetramethylene terephthalate (PBT) and soft segments of poly(tetramethylene ether glycol) (PTMG) was synthesized by four kinds of catalyst: tetrabutyl titanate and magnesium acetate (Ti-Mg); tetrabutyl titanate and triethanolamine; tetra(isopropyl) titanate; and isopropoxy(triethanolaminato) titanate, respectively. Their segment sequence distributions were analyzed by ¹³C-NMR, based on different chemical shifts of aromatic quaternary carbons in the three different triad sequences. The effects of catalyst on sequence distribution and transparency were investigated. It was found that the copolymer has lower probability of B-T-B when Ti-Mg was used as catalysts, and results in higher transparency. © 1995 John Wiley & Sons, Inc.     

Oligomerization of isocyanates by cyclic sulfonium zwitterions

Summary The cyclic sulfonium zwitterions (I) are very effective catalysts for the cyclotrimerization of isocyanates. Under certain conditions (high concentration of isocyanate in the reaction system or high reaction temperature) cyclic sulfonium zwitterions act as anionic initiators. This behavior is due to the reaction of the isocyanate with stabilizing molecules of water of cyclic sulfonium zwitterions followed by rapid polymerization of the initiator. This phenomenon can be easily utilized in the one-step preparation of stable NCO-terminated oligomers of difunctional isocyanates.The support of the Dow Chemical Company is gratefully acknowledged.     

聚醚酯弹性纤维的改性研究

和丙三醇(GL),制备了改性聚醚酯弹性体,经熔融纺丝得到聚醚酯弹性纤维,讨论了TiO_2和GL对弹性纤维性能的影响。结果表明:0.4%～0.8%mol GL的加入和0.5%(w)TiO_2的加入都能提高聚醚酯弹性纤维的弹性回复率。GL的加入还使拉伸断裂强度和模量增加。与未改性聚醚酯弹性纤维相比,两种改性弹性纤维的声速和声速模量随拉伸倍数的增加而幅度下降。     

Poly(sulphopropylbetaines): 1. Synthesis and characterization

The synthesis of aromatic and aliphatic poly(sulphopropylbetaines) is described within the series of vinylpyridines and tertiary amino-methacrylates. Two complementary strategies were used: (a) preparation and free radical polymerization in aqueous solution (60°C, 4,4'-azobiscyanovaleric acid) of the monomers; (b) heterogeneous quaternization of preformed poly(vinylpyridines) and poly(tertiary amino-methacrylates) by 1,3-propanesultone in propylene carbonate or tetramethylene sulphone solution (120°C). The high molecular weight poly (zwitterions) ($\text{10}{}^5\text{<}\text{M}\text{?}{}_{\mathrm{W}}\text{< 5 × 10}{}^6$) were characterized by ultra-violet and ¹H nuclear magnetic resonance spectroscopy, and their water affinity at 20°C was estimated by water vapour absorption measurements.     

P/B Ketene Adduct Formation from Acyl Chlorides at a Vicinal Phosphane/Borane Frustrated Lewis Pair

The intramolecular frustrated phosphane/borane Lewis pair Mes₂PCH₂CH₂B(C₆F₅)₂ ( 3 ) reacts with acetyl chloride to give a 1 : 1 mixture of the FLP-ketene adduct, 6a , and the FLP-HCl addition product, 7 . Similarly, the acyl chlorides phenylacetyl chloride and isobutyryl chloride react with 3 to give the respective substituted FLP ketene adducts, 6b and 6c , with HCl elimination. A series of aroyl chlorides reacts with 3 by formation of the respective aroyl-phosphonium/chloroborate zwitterions, 11a – d . The hetero-aromatic furoyl chloride reacts with 3 in a more complicated, but mechanistically probably closely related pathway, to form the 2 : 1 reaction product, 14 . Most of the products were characterized by X-ray diffraction.     

聚醚氨酯结构与微相分离的研究

以聚四氢呋喃二醇(PTMEG)为软段，以4，4’-二苯基甲烷二异氰酸酯(MDI)和间苯二胺为硬段，合成了一系列聚醚氨酯嵌段共聚物。利用傅立叶红外光谱(FTIR)、差热分析(DSC)和小角X光散射(SAXS)对聚醚氨酯嵌段共聚物的微相分离进行了研究，发现在聚醚氨酯嵌段共聚物中存在两相结构，其微相分离程度随硬段含量的增加而降低。     

Preparation and stability behavior of the colloidal epoxy-1,1-iminodi-2-propanol adducts

Epoxy-amine adduct was prepared by reaction between DGEBA and 1,1-iminodi-2-propanol. The kinetic of the reaction was investigated by differential scanning calorimetry (DSC) and a model-free approach. The epoxy-amine adducts were prepared with various molar ratios of amine functionalities. Waterborne dispersions of these resins have been prepared by neutralization of amine functionalities in the epoxy-amine adducts. Fourier Transform Infrared Spectroscopy (FTIR) and DSC were also used to characterize the prepared epoxy-amine adducts. The stability behavior of the neutralized epoxy-amine adducts has been studied at 25 °C in aqueous solution of acetic acid. In each case, the experimental stability ratios (W) versus electrolyte concentration plots were fitted using the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory and modified Fuch's model. The resulted values of diffuse potentials and Hamaker constants were obtained for the aqueous dispersions of the epoxy-amine adducts. According to the resulted Hamaker values, the applicability of the DLVO theory to the colloidal particles of epoxy amine adducts was investigated. The cathodic electrodeposition behavior of the prepared dispersions were also investigated. It was found that the samples with lower degree of neutralization result in a more efficient film deposition followed by higher dry film thickness although they show lower stability in the electrodeposition bath.     

Interpretation of the enhanced solubility of poly(vinylidene chloride) in certain solvent mixtures

The 3-component mixture poly(vinylidene chloride)—tetramethylene sulfoxide–tetrahydrophalene has been investigated by viscometric methods. This solvent pair shows an unusal affinity for the polymer. This can be attributed to the strong polar interaction between the acidic polymer and the basic sulfoxide which is enhanced by the presence of the nonpolar diluent.     

Zwitterion enhanced performance in palladium–phosphine catalyzed ethylene methoxycarbonylation

Zwitterions were used for the first time as promoters in ethylene methoxycarbonylation for the production of methyl propionate. They were found to improve the catalytic performance of the Pd–phosphine system. The presence of zwitterions could contribute to stabilize transition states and active catalytic Pd intermediates. The beneficial effect of the zwitterions was found to be most pronounced, when low amount of a strong acid (MeSO₃H) was used with respect to palladium (below 2 equiv.). Under these conditions, phosphine ligand alkylation and reaction vessel corrosion are also anticipated to be less severe.     

Copolyester studies. III. Melt-spinning,drawing, and mechanical properties of tetramethylene terephthalate–tetramethylene sebacate copolymer fibers

Fibers have been prepared from tetramethylene terephthalate–tetramethylene sebacate copolymers, containing up to 20 mol % of the latter, using a conventional melt-spinning technique. The mechanical properties of these undrawn fibers and of highly oriented fibers prepared from them have been evaluated. The changes in mechanical properties brought about by the introduction of sebacate groups in poly(tetramethylene terephthalate) have been related to the glass-transition temperatures of the copolymers and to the flexible nature of the sebacate unit. The formation of voids during a continuous drawing process and during mechanical testing is discussed.     

Synthesis, properties of fullerene-containing polyurethane-urea and its optical limiting absorption

Based on the typical two step polyurethane-urea synthesis, self-crosslinkable polyurethane-urea compounded of poly(tetramethylene oxide), MDI (4,4′-diphenylmethane diisocyanate) and extended by AEAPS (aminoethylaminopropyltrimethoxysilane) were prepared. On the other hand, a C60-amine adducts by reacting C60 with excessive APES (aminopropyltrimethoxysilane) were synthesized and introduced into the polyurethane-urea to form the homogenous and transparent C60 containing polyurethane-urea films. FT-IR, UV, Electron Spectroscopy for Chemical Analysis, Wide-angle X-ray diffractions, dynamic mechanical thermal analysis and mechanical properties of samples were recorded. The optical limiting properties were also measured. The results show that the C60 containing polyurethane-urea is a kind of homogenous material with the ranging of C60 content. The solution state before processing makes it easy to be cast as variety configurations. With the difference in C60 content in polymers, the optical limiting properties are various and the required transmittance and transmitted energy can be altered with the C60 contents in polymers.     

Sequence distribution of styrene units in poly(styrene-co-tetramethylene disulfide) obtained from chain transfer copolymerization

Synopsis Copolymers obtained from radical styrene polymerization in the presence of poly(tetramethylene disulfide) were subjected to sulfur-sulfur bond cleavage by butyllithium. The resulting oligo-and poly (styrene) molecular weight distribution is identical with the sequence distribution of styrene sequences in the copolymer which proved to be a multiblock. From this, the apparent chain transfer constant of poly(tetramethylene disulfide) was calculated. The author is indebted to Deutsche Forschungsgemeinschaft and to Fonds Der Chemischen Industrie for financial support.     

聚酰胺6—聚醚嵌段共聚物增韧改性

以聚四氢呋喃醚为软段制备大分子活化剂，引发己内酰胺阴离子聚合，合成了聚酰胺６－聚醚嵌段共聚物，并考察大分子活化剂种类、用量对聚合物力学性能的影响。结果表明，所得制品在保持一定强度、硬度的条件下，冲击性能可大幅度提高，取的了较好的增韧效果。     

Electrospinning of polyurethane fibers

A segmented polyurethaneurea based on poly(tetramethylene oxide)glycol, a cycloaliphatic diisocyanate and an unsymmetrical diamine were prepared. Urea content of the copolymer was 35 wt%. Electrospinning behavior of this elastomeric polyurethaneurea copolymer in solution was studied. The effects of electrical field, temperature, conductivity and viscosity of the solution on the electrospinning process and morphology and property of the fibers obtained were investigated. Results of observations made by optical microscope, atomic force microscope and scanning electron microscope were interpreted and compared with literature data available on the electrospinning behavior of other polymeric systems.     

球形醇镁加合物的脱醇规律

探讨了脱醇方式对球形醇镁加合物组成的影响。采用流化床脱醇方式研究了温度和球形醇镁加合物组成的对应关系;利用二级速率方程对脱醇动力学数据进行了关联,并计算出乙醇与MgCl2的平均络合活化能为43．8ld／mol。采用激光粒度分布测定仪和扫描电子显微镜分别对不同组成的产物进行测定,发现随着醇含量的降低,球形颗粒逐渐变小,粒径分布变窄,MgCl2的次级颗粒结构更加明显。