Titanium polyethers

We have previously synthesized a number of titanium polyethers of the following general structure (3,4). A variety of aromatic and aliphatic diols were successfully incorporated as the fundamental backbone units of the polyethers. These materials are insoluble and do not soften prior to thermal-induced degradation. 

A series of titanium polyethers (repeat unit given below) based on PEG were synthesized (Table 1). The percentage yields were, as expected, similar except for the siloxane ABA block copolymer. In general, there was a slight decrease in percentage yield as the molecular weight of the PEG increased possibly due to size-related factors and the ability of the reactive sites to "get together". 

A number of titanium polyethers derived from hydroquinone derivatives were evaluated employing the T(J-MS assembly and infrared spectroscopy (24). Two general trends were found. 

In many cases, such as in the determination of highly volatile materials (e.g. moisture in nylons or in polysaccharides [412]), or of residual solvents or plasticisers (as in PVB) [413], use of TG-MS is requested. Specifically, there are reports on the entrapment of curing volatiles in bismaleimide laminates [414] and elastomers [415], of plasticisers such as bambuterol hydrochloride [416] or triphenyl phosphate and diethylterephthalate in cellulose acetate [417], on solvent extraction and formaldehyde loss in phenolic resins [418,419]. Carraher et al. [420] have used TG-MS to study the degradation of a fluorescent titanium polyether ester dye. 

Table 1. Results as function of employed base, system and diol for the synthesis of titanium polyethers.° ...

Titanium-containing polyethers have been prepared by the reaction of dicyclopentadienyltitanium dichloride with aromatic and ahphatic diols via an interfacial and/or aqueous solution polycondensation technique (273). 

Certain fillers are commonly added to protect the urethane backbone from oxidative degradation. Carbon black and titanium dioxide are commonly used in conjunction with antioxidants to protect polyether polyurethanes in exterior adhesive applications that may be exposed to oxygen and light (Fig. 12). 

This article will outline firstly the application of RCM technology to the preparation of the epothilones with particular emphasis on the generality and mild nature of the process. The second section will describe the use of cyclopentadi-enyl titanium reagents in metathesis processes and, in particular, their application to the preparation of polyether segments of marine neurotoxins. 

Anticoccidial activity, of polyether antibiotics, 20 135-136 Anticoccidials, 20 135—136 Anticorrosion agents, molybdenum compounds in, 17 39 Anticorrosion coatings, organic titanium compounds in, 25 134 Anti-corrosion metallic coatings, 1 713-714 Anticorrosion pigments, 19 411 Antidegradants... 

Polyester manufacture, organic titanium compounds in, 25 123 Polyester materials, recycling, 20 22 Polyester/polyether/polycarbonate,... 

The two aluminum alkoxide primers on mild steel showed improved adhesion and better resistance to crack propagation with both the thermoplastic polyether-sulfone (PES) and the FM 300U thermoset epoxy adhesive. The titanium alkoxide exhibited the poorest resistance to crack growth, while tetrabutyl orthosilicate showed intermediate behavior between the two aluminum alkoxides and the titanium alkoxide. 

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