Perspectives on additives for polymers. Part 2. Aspects of photostabilization and role of fillers and pigments. Issue 2 (14th December 2020) - Allen, Norman S.
Abstract: In Part I of this two‐part series the most important aspects of antioxidants (primary and secondary), processing aids, metal deactivators and some light stabilizers were described and highlighted together with their mechanisms, problems, and interactions. Emphasis was placed on synergism and antagonism in performances and color problems with a special insight regarding PVC. Part 2 of this article presents in a similar way general perspective on the type, mode of action, properties, uses, problems (and circumvention) of light stabilizers and of some important fillers and pigments. Montmorillonites, silica, carbon blacks, and titanium dioxide will be the main features with an emphasis on structure, activity, and formulations in polymer systems. Additive interactions between stabilizers and fillers/pigments is a major controlling factor in the end use performance from a physical, esthetic, structural, mechanical, and chemical point of view. Indeed, with filled polymers one enters an overly complex world of interactions giving rise to some extreme synergistic and often antagonistic problems which can in many cases destroy or even enhance the activity of functional processing additives. Several of these will be highlighted to provide the technologist with at least some experience such that one can be alert to any potential issues in formulating more complex packages where not just color but high performance is also required. Abstract : This article presents a general perspective on the type, mode of action, properties, uses, problems (and circumvention) of light stabilizers and of some important fillers and pigments. Montmorillonites, silica, carbon blacks and titanium dioxide will be the main features with an emphasis on structure, activity, and formulations in polymer systems. Additive interactions between stabilizers and fillers/pigments is a major controlling factor in the end use performance from a physical, esthetic, structural, mechanical, and chemical point of view. It presents many stability issues in an overly complex world of interactions giving rise to some extreme synergistic and often antagonistic problems which can in many cases destroy or even enhance the activity of functional processing additives.