In this review article, polyurethane (PU) foam materials are presented in various industrial applications. PU foams have started to replace metals and plastics in various engineering applications by combining the hardness and durability of metal with the flexibility of rubber. PU foams can be synthesized with various isocyanates, polyols, chain extenders and crosslinkers to serve many specific applications, such as bio-based composite foam, flexible hard/soft PU foam, polymer foam etc. There are different factors to change of hard and soft segments of PUs. These changes form different products, such as urethane, biurets, allophanates and isocyamurates, etc. This review article mostly concentrates on the basic chemistry of the building blocks of PUs and recent developments in industrial applications of PU foams, such as insulator material, sound insulators, refrigerator and freezing insulators, furniture, shoes, automotive materials, coatings and adhesives and other applications.

Ambalajlama, gıdaların raf ömrünü belirleyen önemli aşamalardandır. Kolay bozulan et ve et ürünlerinin kalitesini korumak ve raf ömrünü uzatmak için yeni paketleme yöntemleri geliştirilmiştir. Antimikrobiyal paketleme sistemleri et ve et ürünlerinde kalite ve güvenliğin sağlanmasında önemli rol oynamaktadır. Amaç, mikroorganizmaların gelişimini belirli bir seviyede tutarak, yavaşlatarak veya durdurarak mikroorganizma gelişimini kontrol etmektir. Antimikrobiyal bileşiklerin gıdaya migrasyonu, çeşitli aktif bileşenlerin tek başına veya ambalaj malzemesine veya ortamına kombinasyon halinde eklenmesiyle sağlanır. Gıda güvenliğinin sağlanması, patojen veya bozulma nedeni olan mikroorganizmalar için bir engel mekanizması oluşturur. Bu çalışmada antimikrobiyal film ve kaplama uygulamalarının kırmızı et ve köftelerde mikrobiyal kaliteye etkileri tartışılacaktır.

It is important to know the behaviours of materials used to design and manufacture farm trailers in the same way as is necessary for all mechanical systems. Fatigue tests for trailers give an idea about the behaviours of its components. Simulators are very useful test systems for applying fatigue tests under laboratory conditions. The aim of this research was to determine the effects of different twisting angles of a trailer chassis on a farm trailer by using a simulator apparatus. Tests were carried out in either static or dynamic conditions. The minimum and maximum twisting angles were selected as 210u and +10u for all tests respectively. The farm trailer was twisted for each 2u and the system was stopped to measure the forces for static conditions. Measured forces were used to calculate the twisting moments. The experimental apparatus ran continuously between 210u and +10u and the forces were measured for each 2u under dynamic conditions. The tests were performed at 26 cycles/min for twisting angles of ¡10u. The energy absorbed through hysteresis by the trailer chassis was calculated as 27 980 N m. The total energy and the coefficient of absorption ability of the chassis were calculated as 107 849 N m and 25.9 per cent respectively. The materials of the trailer chassis must be more elastic than this value according to the literature to absorb vibrations created by the road or field. When the twisting moment of the trailer is smaller, it is possible that the trailer may fall over when going round a bend in the road. Stability requires high twisting moments. The absorption of vibration, however, requires smaller twisting moments.