Effect of Hyperbranched Poly(amine-ester) Grafted Nano-SiO_2 on Reinforcement and Toughness of PVC

Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The composites＇ structures andmechanical properties were characterized by transmission electron microscopy（TEM）, sanning electronic microscopy（SEM） and electronic universal testing machine. The results. show that nano-SiO2 grafted by hyperbranched poly （amine-ester） increases obviously in dispersion in PVC matrix, and mechanical properties of PVC are effectively improved. Moreover, it was found that mechanical properties of PVC/nano-SiO2 composites reach the best when weight percent of nano-SiO2 in PVC matrix is 1%. Compared with crude PVC, the tensile strength of hyperbranched poly （amine-ester） grafted nano-SiO2/ PVC composite increases by 24.68 % and its break elongation, flexural strength and impact strength increase by 15.73%, 4.07% and 1 841.84%, respectively. Moreover, the processing of the composites is improved.

NOVEL HYPERBRANCHED POLY(AMINE-ESTER) FILMS: PREPARATION, CHARACTERIZATION AND PROPERTIES

Crosslinked film of hyperbranched poly（amine-ester） （HPAE） was prepared by crosslinking its terminal hydroxyl groups with glutaraldehyde （GA）. Atom force microscope （AFM） and scanning electron microscope （SEM） reveals that they have smooth surfaces, dense and homogenous matrices. It was found that the water static contact angle is smaller than 41.7°, the tensile strength is higher than 8.9 MPa, the elongation at break is higher than 5.1%, the swelling degree is higher than 42% in water, and the Bovine hemoglobin （Hb） adsorption is relatively low. These results indicate that the crosslinked HPAE films might have some potential applications in many areas.

Utilization of Trimethylolpropane Based Hyperbranched Poly(Amine-Ester) as New Polymeric Admixture

Hyperbranched poly(amine-ester) (HBPAE) was synthesized via pseudo-one-step process between trimethylolpropane as a core molecule and N, N-diethylol-3-amine methylpropionate as the AB2 branched monomer. The prepared polymer was analyzed by IR, GPC, 1H-NMR and thermal analysis (TGA and DSC). The performance of the polymer in cement was tested by measuring the effect of 1, 3 and 5 wt% of HBPAE solutions on the properties of Ordinary Portland Cement. Water of consistency, setting times, bulk density, apparent porosity, compressive strength and combined water content of the polymer/cement pastes were studied. The results showed that water of consistency and apparent porosity decreased while setting times, compressive strength, combined water and bulk density increased with the polymer addition.

Synthesis and application of a novel star-hyperbranched poly(acrylic acid) for improved dental restoratives

A new star-hyperbranched poly(acrylic acid) has been synthesized and incorporated into dental glassionomer cement for enhanced mechanical strengths. The effects of arm number and branching on viscosity of the polymer aqueous solution and mechanical strengths of the formed experimental cement were evaluated. It was found that the higher the arm number and the more the branching, the lower the viscosity of the polymer solution as well as the mechanical strengths of the formed cement. It was also found that the experimental cement exhibited significantly higher mechanical strengths than commercial Fuji II LC. The experimental cement was 51% in CS, 55% in compressive modulus, 118% in DTS, 82% in FS, 18% in FT and 85% in KHN higher than Fuji II LC. The experimental cement was only 6.7% of abrasive and 10% of attritional wear depths of Fuji II LC in each wear cycle. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations.

Reaction and characterization of crosslinking hyperbranched poly(amine-ester) with succine anhydride

Basing on hydroxyl terminated hyperbranched poly(amine-ester)s(HPAEs),the cross-linking reactions and preparation of ester-crosslinked HPAE films were inves-tigated using succine anhydride(SA)as crosslink reagent.It was proved that the cross-linking reaction between HPAE and SA followed a two-step mechanism.This mechanism provides an efficient route to prepare HPAE/SA cross-linked films,in which,the precursor films were prepared by casting HPAE/SA solution at a lower temperature,and then curing the films at a higher temperature.By varying SA content,the solid HPAE/SA films with different cross-linking degrees were prepared successfully.The highest tensile strength of the cross-linked film could reach 59.60 MPa.With all water contact angle smaller than 74.3°,the crosslinked films demonstrated good hydrophilic properties.

紫外光固化超支化聚酯丙烯酸酯/二氧化硅杂化材料的制备

以季戊四醇为"核",2,2-二羟甲基丙酸为支化单体,用逐步聚合的方法合成了不同代数超支化聚酯;将不同代数超支化聚酯分别与六亚甲基二异氰酸酯和丙烯酸羟乙酯半加成产物进行反应,得到一系列超支化聚酯丙烯酸酯低聚物。最后,将得到的超支化聚酯丙烯酸酯低聚物与改性纳米二氧化硅进行复合,得到可紫外光固化的超支化聚酯丙烯酸酯/二氧化硅杂化材料。对合成的超支化低聚物的结构用红外光谱、核磁共振谱和凝胶色谱进行表征。紫外光谱显示所有超支化低聚物在210 nm处有强的紫外吸收。超支化低聚物的玻璃化转变温度用差示扫描量热仪进行测量,结果显示温度范围为-68.68℃到-25.4℃。此外,对紫外光固化超支化聚酯丙烯酸酯低聚物的热性能用热重分析仪进行了表征。

可UV固化的超支化聚脲涂料的合成

用核磁共振、热重分析以及红外光谱对第三代的超支化聚酰胺-胺进行了表征。用甲苯-2,4-二异氰酸酯,丙烯酸羟乙酯以及聚乙二醇-600合成得到聚氨酯预聚体对超支化聚酰胺-胺进行化学改性,得到具有紫外光活性的涂料。用UV灯固化涂料,并用DSC,TGA等技术测试了涂料固化后的热性能。结果表明,超支化聚脲涂料有很高的反应活性,可以直接在空气中固化且表面不发粘,其玻璃化转变温度大约为7℃,热分解温度为302℃。