Dave Dunn Ph.D.

In the plumbing industry, solvent-based PVC cements are used for bonding PVC plastics. However, if you need a solvent-free system, cyanoacrylates and reactive acrylics have been widely used on rigid PVC.

I started my career as a chemist with Loctite Corp., and we used to manufacture our own monomers.

This is a good question for two reasons: first, adhesives and sealants often have to fill large irregular gaps and expansion on curing enables them to achieve this; and second, the products usually shrink on curing.

I suspect that the concentration of your products in the water is very low, but the answer is almost certainly no!

We have some pinhole leaks in an old fire sprinkler system in a large apartment block. Is there an adhesive that will seal those leaks?

Polytetrafluoroethylene (PTFE) is low-surface-energy plastic that is very difficult to bond. PTFE exclusively comprises fluorine and carbon atoms with no polar atoms such as oxygen or nitrogen.

I have seen at least one manufacturer advertising a two-component methyl methacrylate (MMA) adhesive product in a cartridge for the bonding of PVC and CPVC pipes. . . .

What does fumed silica do for adhesives and sealants compared to other thickeners like wood flour or clays, and how do you handle the huge clouds of dust from the bags?

Question: We use some 100% solids methacrylate-based sealants for sealing metal joints. We’re concerned about low adhesive strength, which might cause problems due to stresses generated during temperature cycling. What are our choices?

Question: We are looking to formulate some acrylic adhesives, including ultraviolet (UV) adhesives. Should we be looking at acrylate or methacrylate monomers?