2-ureido-4[1H]-pyrimidone(Upy)telechelic hyperbranched polymers were prepared and their coating performances were investigated.First,a secondary amine terminated hyperbranched poly(ester-amine)(HPEA)was prepared from piperazine and trimethylolpropanetriacrylate at secondary amine/acrylate group ratio of 2.25/1.At secondary amine/isocyanate stoichiometric ratios of 1∶0.3,1∶0.4 and 1∶0.5,HPEA was further reacted with monoisocyanato methylisocytosine to give three modified hyperbranched polymers bearing terminal Upy units.Based on the 1H-NMR spectra of the modified polymers,the degree of modification was calculated,which agreed well with the feeding composition of the components.Due to the formation of self-complementary quadruple hydrogen bonding of Upy groups,the Upy modified polymers possessed improved glass transition temperature(T_g)and decomposing temperature(T_d)compared to HPEA.The coating materials of the modified polymers displayed good mechanical properties.The T_g,T_d and coating hardness became higher as increasing the Upy content.All the coatings possessed impact strength of 0.5 kg·m and flexibility of grade 7.This investigation demonstrated that hyperbranched polymers with improved performances could be obtained via incorporating strong hydrogen bonding,which is helpful for designing new dynamic materials.

A hyperbranched polymer (HPE-1) with quadruple hydrogen bonding units was prepared through reacting Boltorn H20 (HPE) with ureidopyrimidinone (Upy) at hydroxyl and isocyanate group ratio of 4 : 1. The structure of HPE-1 was characterized by H-1-NMR and IR. The melting HPE-1 can form long fibers under pulling due to the strong interaction of the molecules, but HPE can't. With both hydrophilic hydroxyl groups and hydrophobic Upy units, HPE-1 self-assembled into spherical aggregates in water. The aggregate become larger in acidic solutions but dissociate under basic conditions, which provides a way for prepaying sensitive material.

A series of hyperbranched polymers with different contents of ureidopyrimidone(Upy)units were prepared by reacting hydroxyl terminated hyperbranched poly(amine-ester)(HPEA)with monoisocyanato methylisocytosine at —OH/—NCO ratios of 1∶0.13,1∶0.25,1∶0.33 and 1∶0.5,respectively.The melt rheology of the modified polymers was investigated by using a Physica MCR300 rheometer.Due to the formation of self-complementary quadruple hydrogen bonding of Upy groups,the modified polymers demonstrated strong temperature and frequency dependent characters in melt rheological properties,and the dissociation temperature appeared to increase as more Upy units existed in the samples.The results indicated that at the low frequency range,the complex viscosity decreased,the storage modulus became larger as increasing the frequency.However,at the high frequency range,the samples displayed shear-thickening behavior,and the storage modulus decreased sharply to rather low values as increasing the frequency.Meanwhile,the loss modulus seemed to increase as elevating the frequency at all frequency range.Such uncommon rheological performance could be explained based on the disruption of Upy micro-domains by shearing force and the formation of quadruple hydrogen bonds between the released Upy units.This investigation is helpful for understanding the rheological behavior of Upy contained polymers and designing new dynamic functional materials.

Hyperbranched poly(amine–ester)s bearing self-complementary quadruple hydrogen bonding units display excellent mechanical and temperature-dependent melt rheological properties, which make them suitable as novel hot-melting materials.

The water resistance and mechanical properties of polyurethane coatings were improved by the reaction between carboxyl and aziridinyl groups for ambient curing of waterborne polyurethane coatings.The waterborne carboxylic polyurethanes and aziridinylic polyurethane cross-linking agent were synthesized from toluene diisocyanate,polyethylene glycol,2,2-dimethylolpropionic acid,glycolic acid and 1-aziridinyl ethanol.Their structures were characterized by 1H NMR.The thermal properties,water resistance,and mechanical properties of the coatings were then investigated.The results indicate that the two components are compatible and the cured coatings possessed excellent water resistance and mechanical properties.

Nano-sized calcium carbonate (CaCO3) particles were modified by heptadecafluorodecyl trimethoxysilane under acidic water condition. An ordinary polyacrylate prepared via radical copolymerization of methyl methacrylate, butyl acrylate, acrylic acid and β-hydroxyethyl methacrylate was used as the binder to form hydrophobic coatings with the modified CaCO3. Super hydrophobic coating with water contact angle of 155° was obtained from modified CaCO3 and the polyacrylate at their weight ratio of 8/2 by a simple procedure. Based on surface analysis by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), the super hydrophobicity can be attributed to both the surface microstructure and surface enrichment of fluoroalkyl chains. Due to a low water sliding angle, carbon black powder on super hydrophobic surface was easily removed by rolling water droplet. Furthermore, the anti-frosting performance of different surfaces was investigated, which indicated that the frost formed on superhydrophobic surface was greatly retarded compared with that on bare copper surface. The surface kept super hydrophobicity even after freezing–thawing treatment for 10 times.

Two well-defined diblock copolymers with quadruple hydrogen-bonding groups on one block, denoted PSUEA-1 and PSUEA-2, have been synthesized, and novel snowflake-shaped nanometer-scale aggregates, self-assembled by such diblock copolymers in non-polar solvents, have been observed. The micellar dimensions were investigated by DLLS and SLLS. Their morphologies were studied by TEM. Since the degrees of polymerization of the Upy-containing blocks of PSUEA-1 and PSUEA-2 are quite similar and the polystyrene block of the PSUEA-1 is longer than that of the PSUEA-2, a subtle but identifiable difference between the sizes and structures of the PSUEA-1 and PSUEA-2 aggregates was noticed and characterized.

The mechanism for rheological modification of ultra-high-molecularweight polyethylene(UHMW-PE) by hyperbranched poly(ester-amide)(PF__2) was investigated by scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy (XPS) analysis of PF__2/UHMW-PE blends.The results show that there is more PF__2 at the surface than in the center of the blend.Shear forces cause the PF__2 molecules to aggregate at the surface of the blends,thus reducing the apparent blend viscosity.The intermolecular adhesion of UHMW-PE was improved by the presence of PF__2.

A hyperbranched poly(ester-amide) (defined as PQ_2) was prepared by melt polycondensation of a pseudo AB2 monomer, N-(3-acetoxyl propyl)-N-(2′, 4′-dicarboxylic benzoyl)amine at 220 ℃ under reduced pressure. The obtained polymer was graded into three parts by precipitating method. The insoluble part in cold DMSO was defined as PQ_2(H) and the soluble part in DMSO was further precipitated into methanol to obtain precipitate defined as PQ_2(L).The two grades can be dissolved in hot DMSO and trifluoroacetic acid. They both possess T_d higher than 350 ℃ and are used to modify the rheology of polycarbonate (PC). With addition of 3% of PQ_2(H) and PQ_2(L), the melting index of PC/PQ_2 melts are (3.1) and (4.7) times of that based on pure PC, respectively. Furthermore, the mechanical properties of PC/PQ_2 blends were also measured. The results indicate that both grades decrease the elongation at break to some extend with little influence on the tensile strength for the blends.