Temperature, environmental sensitivity

Thermoresponsive enhances decomplexation below critical solubility temperature Environmentally sensitive disulfide bonds... 

Health and safety factors in in situ operations are associated with high temperature, high pressure steam, or high pressure air. Environmental considerations relate to air and water quaUty and surface reclamation. In some environmentally sensitive areas such as the oil sands deposits in Utah, environmental considerations may make development unfeasible. 

Foam fluids can be used in many fracturing jobs, especially when environmental sensitivity is a concern [1669]. Foam-fluid formulations are reusable, are shear stable, and form stable foams over a wide temperature range. They exhibit high viscosities even at relatively high temperatures [209]. 

Another class of environmentally sensitive materials that are being targeted for use in drug delivery applications is thermally sensitive polymers. This type of hydrogel exhibits temperature-sensitive swelling behavior... 

Both nuclear and conventional power plants produce environmentally-sensitive waste. Both use cooling water which when put into streams and rivers while still at elevated temperatures can cause significant damage to the biota. 

Bermen, J.M., Graham, J.L., and Dellinger, B., High temperature UV absorption characteristics of three environmentally sensitive compounds. J. Photochem. PhotobiolA Chem, 68 353-362, 1992. 

Table 3.2 also includes data for the advanced thermoplastic resins (PEEK) and for a thermosetting resin, an end-capped bismaleimide (BMI) called PMR-15. Moisture contents tend to be lower for these advanced materials [12,13]. One way to overcome the environmental sensitivity of epoxide resins is to employ these advanced resins, as demonstrated in Table 3.2. However, changing to other resin systems brings with it other concerns. For example, PEEK relies on crystallinity for its higher temperature performance. Its glass transition temperature is only 143°C and a change in modulus can be observed at that temperature. In addition, higher process temperatures are required both for high performance thermosets and thermoplastics. The consequent higher residual thermal stresses can off-set some of the advantages of a higher service temperature, in comparison with advanced epoxy resins.

The membrane with the nanometer-sized holes can be used as template of metallic replicas. The holes are filled up with some metal atoms by electrolysis in a galvanic cell, and after deposition, the membrane is removed mechanically or by a suitable solvent. In these ways, little rods with a few pm length and few times 10 nm diameters are produced (Tagawa et al. 2004 Coqueret 2008). By grafting environmental sensitive polymers on the surface of the holes, the permeability of the membrane can be regulated by external signal (temperature, pH, etc.). The operation of such systems may mimic, the operation of biological membranes. 

Smart hydrogels can change their volume by a large fraction in response to many stimuh, such as temperature, pH, ions concentration, solvent composition and light irradiation. This environmental sensitivity plays an important role in achieving new technological and scientific applications. 

Stimuli-sensitive or smart polymeric systems are defined as the polymers that might rise above dramatic property changes replying to minute changes in the environment [50]. The effect of different stimuli on environmental sensitive polymers (Figure 9.35) has been widely studied, and among these temperature is the most investigated stimulus since it is directly related to the human body [51]. 

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