Lime repellent polyethylene additives

The precipitation of calcium carbonate from hard water, commonly known as calcification or scaling, is a widespread nuisance. To avoid scaling, a physical or chemical pretreatment of water is often employed, such as ion exchange, addition of complexing agents, or the use of magnetic and electric fields. Our approach is to construct surfaces to which calcium carbonate crystals do not adhere. Here, we show that by the use of particular copolymer additives, polyethylene can be made lime repellent. The copolymers have the formula: polyethylene-block-poly(ethylene glycol) and are compounded into the polyethylene. Twelve such additives were investigated and three displayed anticalcification activity. The effective copolymers were investigated by mass spectrometry. Infrared spectroscopy of copolymer/polyethylene blends revealed that the concentration of the additive in the matrix correlates to a specific absorption band. Stability tests against hot water showed that the anticalcification activity was maintained over the timeframe investigated.