(plastech) -- The global demand for thermoplastics is expected to grow by around 100,000 tonnes by 2015, driven by the developing economies. Polyethylene comprises 35% of this market and polypropylene is 24%, according to leading market consultant Noru Tsalic of Applied Market Information (AMI).
This is an annual increase of 5.6%. The key applications for PE are packaging at 69% and infrastructure at 11%, while for PP the percentages are 43% in packaging and 11% in automotive and appliances.
The leading material suppliers conduct extensive research, like Borealis Polyolefine. Molecular structure, processing and additives all affect properties. Stabilisers and modifiers need to be compatible with the polymer, have high solubility and low migration rate and meet all safety standards. The range used in polyolefins includes antioxidants for processing and long-term stabilisation, UV stabilisers, antistatic, slip agents, nucleating agents, flame retardants, impact modifiers, lubricants, foaming agents, fillers and reinforcements.
It is also important that recipes take account of synergistic or antagonistic effects of additive combinations, for example hindered amine light stabiliser (HALS) is antagonistic to sulfur antioxidants. Some additives have dual effects, for example nucleating agents can improve thermal stability, perhaps because of the increase in crystallinity. Fillers are particularly important as the chemical nature, particle morphology and surface treatment can all affect material performance and additive interaction.