A series of thermoplastic poly(imide-urethane)s (TPIUs), based on 4,4′-diphenylmethane diisocyanate (MDI) and pyromellitic anhydride (PMDA) as hard segments and poly(tetrahydrofuran) (PTMG) as soft segments, has been prepared by a two-step polymerization process. The objective of this study is to prepare a type of intrinsically flame-retardant polyurethane by incorporating PMDA as a flame retardant in the main chains. The thermal behavior and flame retardancies of the TPIUs have been characterized by thermal gravimetric (TG) analysis and limiting oxygen index (LOI), UL-94 vertical burning, cone calorimeter tests. The results indicate that the TPIUs display outstanding performance. The temperature at 5% mass loss (T_5%) and LOI value increase with the hard-segment contents, while the total heat released (THR) and peak heat release rate (p-HRR) show the opposite trend. Furthermore, the T_5% of TPIU211 (molar ratio: MDI : PTMG : PMDA = 2 : 1 : 1) is 33.2°C higher than that of the conventional thermoplastic polyurethane TPU211 (molar ratio: MDI : PTMG : 1,4-butanediol = 2 : 1 : 1), and the THR and p-HRR of TPIU211 are 14.62% and 64.02% lower than the respective parameters of TPU211. In addition, UL-94 vertical burning tests show that the TPIUs exhibit excellent antidripping effects. The ultimate tensile strengths of the TPIUs reached 23.1−37.6 MPa with increasing hard segment contents, which meets the requirement of mechanical properties with regard to practical use. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40801.

Reactive hot-melt polyurethane adhesive (RHMPA) is moisture-curing polyurethane (PU) adhesive whose main component is an isocyanate-terminated PU prepolymer that can be cured after application by reaction with ambient moisture. Two series of RHMP-containing poly(tetramethylene glycol) (PTMG) of different molecular weights and different degrees of polymerization of the hard segment have been successfully synthesized using a two-step bulk polymerization with 4,4′-diphenylmethane diisocyanate, PTMG, and 1,4-butanediol (1,4-BDO). The structure and basic properties of the RHMPA film have also been characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, atomic force microscopy, gel permeation chromatography (GPC), shore hardness (A/D), and tensile tests. The results show that the initial decomposition temperature is more than 250°C, and the tensile strength of the RHMPA film was greater than 15 MPa. The adhesive performance of the RHMPA with different hard-segment content was studied through studies of the single lap-shear strength and tensile strength of butt joints. The results show a general trend of the bonding strength increases with the hard-segment content at 25°C. The adhesive performance of RHMPA in different environments was also investigated. It was found that the RHMPA exhibited excellent bonding strength to thermoplastic polyurethane elastomer (TPU) when placed in the fridge at −20°C, hot water at 80°C, 1 M HCl solution (acid) at 25°C, and 1 M NaOH solution (alkaline) at 25°C for 10 h. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A novel polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane (OPAPS, (SiO_1.5C₆H₄NHCH₂CCH)₈) was prepared from octa(aminophenyl)silsesquioxane and propargyl bromide. The chemical structure of OPAPS was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance, X-ray diffraction (XRD), high-performance liquid chromatography, gel permeation chromatography, differential scanning calorimetry, and thermal gravimetric analysis (TGA). The structure of the thermally cured polymer of OPAPS was characterized by FTIR, XRD, and TGA. It had good thermal stability. TGA demonstrated that the thermal decomposition temperatures (T_d5) of the cured OPAPS polymer in nitrogen and air were 455.6 and 458.8°C, respectively. The thermal curing reaction kinetics of OPAPS were studied and some kinetic parameters were obtained. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

This work aims to study the impact of the degree of polymerization (Pn) on the rheological behavior of PVA solutions (15 wt %) under steady and oscillatory shear conditions. The values of Pn range from 1300 to 2400. The results show that PVA-13 solution exhibits almost Newtonian flow behavior, whereas high Pn PVA solutions exhibit shear thinning behavior, for which the complex viscosity increases with Pn. However, the shear viscosity of PVA-24 is lower than that of PVA-20 at low shear rate (<1 s⁻¹). In addition, the storage modulus of PVA solutions increases with increasing degree of polymerization from 1300 to 2000. There is a sharp increase at degrees of polymerization higher than 1300. However, the storage modulus of PVA-24 is lower than that of PVA-17 and PVA-20 at low shear rate (<1 rad/s). The viscoelastic exponent of the PVA solutions shows a minimum value at degree of polymerization 2000. Thixotropy is detected by a hysteresis loop of the flow curves. The creep response of PVA solutions has also been investigated, with PVA-24 showing negligible compliance recovery. These facts indicate that increasing Pn produces a corresponding effect in varying the molecular structure and types of hydrogen bonding, including intra- and inter-chain, and polymer–water hydrogen bonding. Rheological parameters (G′, n, tanδ, J, and so on) can be used to evaluate the change in the molecular structure and type of hydrogen bonding. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010