Performance materials group Low & Bonar has appointed Steve Good as chief executive with immediate effect and said it expects second half profit to be 'materially improved' compared to the first half.Good's appointment follows the resignation of Paul Forman who is leaving Low & Bonar after seven years to become chief executive of sewing thread and needlecraft products firm Coats.The group said that the encouraging improvement in sales patterns seen in the period up to 13 July, the date of its interim results announcement, has been maintained.