Traditional coupling agents

CASE 14.1 COUPLING AGENTS IN LONG-GLASS-FIBER PP [14-7] 

Problem Some new LF-PP formulations are not yet optimized for costs and properties 

Objective Determine how to minimize the costs of the expensive components In LF-PP, such as the g-MAH coupling agent. 

Solution New grades of glass fiber allow reduced coupling agent use. 

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Although this compound is not a traditional coupling agent, it does provide for a biologically effective interface between microbes and a variety of surfaces, and... 

Eatty bisamides are used primarily to kicrease sHp, reduce blocking, and reduce static ki polymeric systems. Other specialty appHcations kiclude cosolvents or coupling agents for polyamide reskis, fillers for electrical kisulation coatings, additives for asphalt to reduce cold flow, and synthetic waxes for textile treatments (68). Bisamides have been used ki all the traditional primary amide appHcations to kicrease lubricity and have become the amide of choice because of thek better efficiency. Bisamides have the highest commercial value ki the amide market. 

Carbon black-silica dual phase fillers reduce hysteresis while maintaining or improving abrasion. This system is less expensive as coupling agent requirement is less and produces semicon-ductive product compared to full silica-filler system. Dual phase filler is less abrasive to the processing equipment compared to the usage of silica filler alone, but use of dual phase filler increases cost of compound compared to traditional carbon black. 

Even the traditional methods discussed in this chapter can be used for concentrated dispersions through contrast matching. For example, silica particles coated with silane coupling agents in a refractive index-matched mixture of ethanol and toluene can be used in combination with visible probe particles to study the dynamics of particles in dense systems. In the case of microemulsions (Chapter 8), selective deuteration of a component (oil, water, or surfactant) can be used in neutron scattering experiments even to measure the curvature of the oil-water interface. 

Cationic surfactants can also be used as functional additives in traditional chain lubricant formulations, including biocides, stress-craze inhibitors and coupling agents. As mentioned above, the first use of alkylamines in chain lubricants was as an additive in a traditional, soap-based formulation to improve the stability of the system. Ethoxylated amines have also been employed as coupling agents in an alkaline diamine track lubricant, while tertiary amines have found utility as saponifying agents in traditional, soap-based chain formulations. 

Comparative studies Unlike traditional inotropic agents, levosimendan is thought to have a lower potential to cause dysrhythmias, because it does not increase intracellular calcium concentrations and myocardial oxygen consumption. Levosimendan and dobuta-mine have been compared in 50 patients with acute decompensated heart failure (NYHA class III-IV, ejection fraction <35%), mean age 68 years [20 ]. Heart rate and the number of ventricular extra beats increased significantly during infusion of levosimendan and dobutamine, but the increase in ventricular coupled beats was significant only with dobutamine. There were more episodes of non-sustained ventricular tachycardia and paroxysmal atrial fibrillation with levosimendan, but the difference was not significant. 

New Developments, A combination of new developments have recently stimulated a remarkable reintroduction of zinc as a coupling agent in traditional Barbier-type synthetic procedures. 

The definition of the term coupling agent, as used in this chapter, has been described earlier. As the nonpolymer component being coupled may be in fiber or particulate form and may or may not be a reinforcement in the traditional sense, the general term inclusion is used here for this component. 

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