Abstract:
Novel hyperbranched segmented copolymers include at least one oligomer. Spacing of branch points in a hyperbranched hyperbranched polymer (A2Bn)x are manipulated by having either A2 or Bn or both A2 and Bn be in the form of an oligomer (as opposed to a monomer).
Abstract:
Using novel synthetic techniques, siloxane-urea segmented copolymers are made. The copolymers advantageously contain a polyether interface, with controlled morphologies and properties. High molecular weight, high strength siloxane-urea copolymers with urea hard segment contents ranging from 5 to over 60% by weight may be prepared. Polymer properties that can independently be controlled include modulus (1.0 to 120 MPa), ultimate tensile strength (1.5 to 25 MPa), level of equilibrium water absorption (~ 0 to 100% by weight) and refractive index (1.43 to 1..46).
Abstract:
Novel segmented polyurethaneurea copolymers were synthesized using a poly(ethylene-butylene) glycol based soft segment. Dynamic mechanical analysis (DMA), small angle X-ray scattering (SAXS) and atomic force microscopy (AFM) established the presence of a microphase-separated structure in which hard microdomains are dispersed throughout a soft segment matrix. Wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) results suggest the materials are amorphous. Samples that are made with HMDI/DY and have hard segment contents in the range of 16-23 wt% surprisingly exhibit near-linear mechanical deformation behavior in excess of 600% elongation. They also show very high levels of recoverability even though their hysteresis is also considerable. The materials are both melt processable and solution processable.