The University of Western Ontario

Fujitsu Corporation

I.c.s.t., the Institute for Chemical Science and Technology

The Institute for Chemical Science and Technology

Renate Foerch

Duncan H Hunter

N Stewart McIntyre

Jun Kodama

Blair Alfred Graham

George S Castle

Rana N Sodhi

Mary J Walzak

A method for grafting maleic anhydride groups to the surface of polyolefins s described. The method uses an excited inert gas phase species in contact with the polyolefin and solid maleic anhydride. The surface functionality is identified by X-ray photoelectron spectroscopy and transmission Fourier transform infrared spectroscopy. The modified polyolefin has an increased ability to form a thermal bond with metals, including aluminum.

Plasma assisted grafting of maleic anhydride to polyolefins

Surfaces of fine polystyrene (PS) and polymethyl methacrylate (PMMA) powders were modified by exposure to the downstream products of a nitrogen or oxygen microwave plasma. The effects of nitrogen and indium incorporation in the powder surface were studied with emphasis on variations in the triboelectric properties of the powder. X-ray photoelectron spectroscopy (XPS) was utilized to determine the changes in surface elemental composition. After nitrogen plasma treatment, the C 1s peak profiles suggested the formation of amines in the case of PS, and the formation of imines and amides in the case of PMMA. Oxygen plasma treatment suggested the formation of hydroxyl and carbonyl groups on the surfaces of both PS and PMMA. After treatment with a nitrogen or oxygen plasma, the charge-to-mass ratio (Q/M) of PS and PMMA powders in contact with carrier particles was measured using the cage blowoff method. The surface charge density (Q/A) was calculated from Q/M. The Q/A of nitrogen plasma-treated PS powder was seen to shift towards positive charge with small increases in the nitrogen concentration. The Q/A of oxygen plasma treated PS powder initially shifted toward negative charge, but changed towards positive charge with higher oxygen concentrations. Plasma-treated PMMA powder showed a different behaviour and the variation of Q/A on PMMA was much less than that of PS. Results suggest that triboelectrification of the polymer powder may be related to changes in the electrical surface states, and that nitrogen may act as a group V dopant within the PS surface.

Plasma treatment of polymer powders

Improved modification of polymer surfaces is achieved by two-step reactions on polymer surfaces, particularly where at least one of the steps is a 'downstream' or remote plasma treatment. For example, polymers may be treated with various combinations of the following: (1) downstream nitrogen plasma treatment; (2) ozone treatment; (3) corona discharge treatment; (4) downstream oxygen plasma treatment; or (5) downstream hydrogen plasma treatment.

Modification of polymer surfaces by two-step reactions

Growing community of inventors

Oestrich-Winkel, Germany

Renate Foerch