Silent Paint

Latex IPNs. Latex IPNs are the third type of IPNs and are manufactured according to the general schematic illustrated in Figure 3. Latex IPN synthesis involves the initial synthesis of a crosslinked seed polymer, usually in the form of an aqueous latex. The seed latex is then swollen with a second monomer/crosslinker/initiator system which is then polymerized "in situ" to form an aqueous IPN emulsion. Materials of this type are best suited to coating applications as illustrated by the development of "Silent Paint" by Sperling et al ( ). However, latex IPNs are limited to water emulsifiable monomer/polymer systems, most of which have fairly low service temperatures, less than 150 C. 

An early attempt to utilize the vibration absorbing effect of an IPN mixture was made by Sperling et al (4), who produced Silent Paint, of which one layer was an IPN. Hourston et al (5) illustrated typical IPN behavior in a 1 1 weight ratio Polyethylacrylate/Polyethylme-thacrylate latex IPN. A continued need for similar types of materials has prompted investigation of all polymeric materials known to be effective energy absorbers. 

Damping Behavior of Silent Paint . The damping behavior of a typical "Silent Paint" composition, cross-polv(ethyl methacrylate)-inter-cross-poly(n-butyl acrylate) 25/75, constrained with epoxy resin, was then compared with several commercial materials as a function of temperature. Figure 3. The "Silent Paint" composition, curve A, damped effectively over a broad temperature range whereas the commercial materials, curves B and C [poly (vinyl acetate) ], and D, E, and F, of various compositions, damped effectively over narrower temperature ranges. 

It is apparent from Figure 3 that the "Silent Paint" formulation enables useful damping over a temperature range from -20 to +50 C, as evidenced by a nearly constant percent critical damping. Transitions in the epoxy material immediately above the latex IPNs transitions increase the effective damping range to to +90 C. 

Figure 13.14. Damping as a function of temperature. The quantity A is the amplitude of the damped reed, and is the undamped reed. E is an epoxy material, F is a polyvinyl acetate material, S is an acrylic house paint, and D is the prototype Silent Paint. (Sperling and Thomas, 1974 Sperling et al, 1974.)...

L. H. Sperling, T.-W. Chiu, R. G. Gramlich, and D. A. Thomas, Synthesis and Behavior of Prototype Silent Paint, J. Paint Technol. 46,47 (1974). Constrained layer damping. Latex IPNs. Methacrylic/acrylic compositions. 

Researchers at Texas A M University discovered that mood, blood pressure, and surgery recovery time can be influenced by art — but not just any kind of art. Patients who had Picasso reproductions in their rooms fared worse than those with blank walls, while some of those who gazed at Monet s water lilies recovered more quickly. I think Hans Selye must have loved beautiful paintings, too. After all, he was himself an artist of sorts. He carved part of the cortisol molecule into the cement outside his window when he was living on Milton Street near McGill. It s still there — a silent testimonial to the man my parents dragged me to see on that stressful day so long ago. 

Living in a house with lead paint is like having a lion sleeping in your living room. You ve got a dangerous situation. The difficulty lies in how to cage it without awakening it—lest it devour your children. And the saddest part of it all is that when it pounces you won t even hear its silent roar. 

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