In the paper, a new biodegradable polyurethane (PU, PU-I) was prepared: the prepolymer was synthesized via bulk ring-opening polymerization with poly(ethylene glycol) (Mn = 600) (PEG600) as an initiator and l-lactide (l-LA), ɛ-caprolactone (CL) as monomers, and the prepolymer was chain-extended with an isocyanate-terminated urethane triblock (macrodiisocyanate) to prepare the PU. The macrodiisocyanate, prepolymer and PUs were characterized by 1H NMR, 13C NMR, FT-IR, high resolution mass spectrometry (HR-MS), gel permeation chromatography (GPC), thermo gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The corresponding PU films showed excellent mechanical properties with a tensile strength of 27.5 MPa and an elongation at break of 996%, and also maintained mechanical properties in physiological saline at 37 °C for more than three weeks, which appeared to be more suitable for biomedical applications.Two clearly Tg being observed in DSC thermogram indicated a micro-phase separation in PU-I. The corresponding PU films showed excellent mechanical properties with a tensile strength of 27.5 MPa and an elongation at break of 996%.

In this paper, polysiloxanes with pendant quaternary ammonium and polyether segments (EQAPS, nonionic–cationic silicone surfactant) were synthesized through hydrosilylation of poly(dimethylhydro)siloxane with allyl poly(ethylene glycol) acetic ester (Mn = 540) and allyl glycidyl ether, followed by a ring-opening reaction of epoxide groups with diethyl amine and quaternization with benzyl chloride. The chemical structures of EQAPS and intermediate products were characterized by 1H-NMR and FT-IR spectra. The surface activity and thermal properties of EQAPS were studied with surface tension measurement and differential scanning calorimetry analysis, respectively. The results showed that the EQAPS had a much smaller critical micelle concentration value (118 mg/L) and lower glass-transition temperature (Tg: −57 °C). The silyl-terminated polypropylene oxide waterborne emulsions, which were substantially free from organic solvent, were prepared via a phase-inversion emulsification technique using EQAPS as single emulsifier and/or poly(ethylene glycol) (\(\bar{M}\)n = 400) as cosolvent. The electrical properties of the system indicated that the phase inversion was completely accomplished. The viscosity of the emulsions with different solid contents was measured, and the results showed that the most suitable solid content was about 50 wt%. The emulsions with smaller particle size (12 μm) had better storage stability (48 days at 50 °C) and freeze–thaw stability.

In this paper, polysiloxanes with pendant quaternary ammonium groups (QAPS, cationic silicone surfactants) were synthesized through hydrosilylation of poly(dimethylhydro)siloxane with allyl glycidyl ether, then ring-opening reaction of epoxide groups with diethyl amine and quaternization with benzyl chloride. The chemical structures of QAPS and intermediate products were characterized by 1H NMR and FT-IR. The surface and thermal properties of QAPS were researched through surface tension measurement and differential scanning calorimetry analysis. The results showed that the QAPS had reduced critical micelle concentration values and lowered glass-transition temperatures (Tg). Waterborne silyl-terminated polypropylene oxide emulsions were prepared via phase-inversion emulsification using QAPS and polyoxyethylene octylphenyl ether (OP-10) as composite emulsifiers and poly(ethylene glycol) (\(\overline{M}_{n}\) = 400, PEG 400) as cosolvent. The electrical properties of the system indicated that the phase inversion was completely accomplished. The emulsions with smaller particle size (6.2 μm) had better storage stability (47 days at 50 °C) and freeze–thaw stability.

The paper presents a new method to prepare waterborne anionic alkoxysilane-terminated polyurethane dispersion (SPUD) which is substantially free from organic solvent: the NCO-terminated polyurethane (PU) containing carboxylic ions in backbone is synthesized by melt polycondensation with toluene 2,4-diisocyanate (TDI), polypropylene oxide (PPO) and 2, 2-dimethylolbutanoic acid (DMBA), the terminal NCO groups are reacted with 3-aminopropyltriethoxylsilane (APTES) to give alkoxysilane-terminated PU (SPU), and the waterborne SPUD with higher aminosilane content (10 wt% in SPU) is obtained by phase-inversion emulsification with the aid of protective colloid (polyethermethylsiloxanes, PEMS) and external emulsifier (sodium dodecyl sulfate, SDS). The anionic PU and SPU are characterized by FT-IR, gel permeation chromatography (GPC), differential scanning calorimeter (DSC) and thermo-gravimetric analysis (TGA). The thermal studies show that SPU has lower Tg than anionic PU as well as thermal stability. The effects of emulsifier, protective colloid, solid content and pH value on the storage stability of waterborne SPUD are investigated, respectively. The results indicate that the storage stability decreases with increasing viscosity and dispersing ratio, whereas particle size and polydispersity index (PDI) are hardly affected by the solid content, the amount of emulsifier and protective colloid. The SPUD prepared with about 2 wt% SDS, 5 wt% PEMS, 31 wt% solid content and pH value of 7 is stable for more than 6 months at 50 °C and 8 months at room temperature, while exhibiting excellent freeze-thaw stability. The corresponding cured films exhibit excellent mechanical properties with 19.2 MPa tensile strength and 320 % elongation at break.

In this paper, thermoexpandable polymeric microspheres were prepared by suspension polymerization with acrylonitrile (AN) and methyl methacrylate (MMA) as monomers and i-butane as a blowing agent. The micromorphology and thermal stability were researched by polarized microscopy and TGA. The diameter of the expandable microspheres increased from about 20 μm (unexpanded) to 40–80 μm (expanded) upon heating. The maximum expansion volume was higher than 22 times of the original volume and the density of the expanded microspheres was about 16.7 kg/m3. The blowing agent content in microspheres was about 20 wt% and To.e., Tm.e. and To.s. were 80 °C, 120–130 °C and 140–145 °C, respectively.The diameter of the expandable microspheres increased from about 20 μm (unexpanded) to 40–80 μm (expanded) upon heating, the maximum expansion volume was higher than 22 times of original volume, To.e., Tm.e. and To.s. were 80 °C, 120–130 °C and 140–145 °C, respectively.