Physical Properties of Aliphatic and Aromatic Polyurea-Nanoclay Composites

摘要

Nanoclay reinforced polymer composites improve multifunctionalities such as structural and thermal properties [1-2]. Understanding the mechanisms involved in improving the mechanical strength of polyurea with nanoclay is important in developing appropriate composite material for the blast and fragmentation resistant applications. Positron lifetime, magnetometry, tensile strength, and thermo mechanical measurements are used to study 1-5 wt% nanoclay incorporated aromatic and aliphatic polyurea films. The first set of organoclay-polyurea composites have been prepared from castable aliphatic and aromatic polyaspartate polyurea systems acquired from Bayer Materials Research Company. These systems consist of aliphatic and aromatic diisocyanate resins, respectively. Commercial nanoclay product, Cloisite 15A, functionalized with a quaternary amine containing a C14-C18 long-chain alkyl tails, was obtained from Southern Clay Products. The nanoclay powder was exfoliated by placing it into a Component B (which is a mixture of secondary polyetheramines) and then stirred at 80 C for 3 hrs. This was followed by degassing of the dispersion and of aliphatic or aromatic resin (component A) in vacuum oven at 75 C. The components were then manually mixed in desired ratio to get 2 wt% nanoclay in case of aliphatic PU and 1 wt% of the same nanoclay in case of aromatic PU, then cast into a Teflon mould and left for curing overnight. A second set of aliphatic polyurea composites was prepared with 1-5 wt% nanoclay dispersion carried out with similar methodology used for Set 1; however, the mixing procedure was performed differently, by placing the PU components A and B into a dual cartridge gun equipped with a mixing pipe dispenser purchased from PLUS PAK.