兼有亲水性、疏水性侧链的三元共聚体的粘附特性和抗血栓性(续)

3　结果与讨论3.1　Ｘ射线光电子分光在表 3中列出了与碳原子 (10 0 )相对应的氧原子及硅原子的比 ,而碳原子 10 0是由ＸＰＳ测定结果计算出来的。Ｏ1ｓ/Ｃ1ｓ比值 ,在ＥＡｘ和ＥＡｘ -Ａ5所有试样中 ,都是脱出角 90°的要比 15°的大。而且 ,对所有的试样来说 ,15°的值都比由组成比计算出的值要大 ,数值范围为 4 5～ 4 8。对于Ｏ1ｓ/Ｃ1ｓ比ＥＡｘ-Ａ5系要比ＥＡｘ系的值略高一点。在这里试样侧链Ｏ1ｓ/Ｃ1ｓ比 ,无论是ＭＰＥＧ侧链 ,还是ＰＤＭＳ侧链都为 5 0 .0。脱出角为 15°的Ｏ1ｓ/Ｃ1ｓ比接近于 5 0 ,所以 ,可认为在ＥＡｘ系、ＥＡ…     

Synthesis and properties of polyimides having alkyloxycarbonyl side chain

Summary A series of polyimides having alkyloxycarbonyl side chains were synthesized from dialkyl 2,5-bis(4-aminophenoxy)terephthalate and PMDA. The inherent viscosities of poly(amic acid)s were in the 1.42~0.63dL/g range. The polyimides exhibit typical 2-step thermal degradation, and lowered transition temperature for longer side chain. Wide-angle X-ray diffractograms revealed that all polymers are partially crystalline, and layered structures were observed for polymers with longer side chain. The pretilt angle is in the 8°~10° range, and increases as the length of the side chains increase.     

Shape memory properties of polypeptide hydrogels having hydrophobic alkyl side chains

Polypeptide hydrogels were prepared by cross-linking of hydrophobically-modified poly[N⁵-(2-hydroxyethyl) l-glutamine] having alkyl side chains –C_nH_2n+1. Chain length of the alkyl group was n = 8, 16, and 18, and their mole fractions in the polypeptide were varied in the range of 0.05–0.16. Shape memory ability of the prepared polypeptide hydrogels was investigated. After deformation at 60 °C, the hydrogel was cooled in order to fix the temporary deformed shape. It was found that crystallization of the alkyl side chains did not occur, and the fixation ability of the hydrogel at 0 °C was low. In the subsequent heating process, the deformed temporary shape spontaneously recovered to the original shape gradually with increasing temperature, in other words, the shape recovery ratio varied with depending on the recovery temperature. From these observations, it was proposed that the shape fixation of the polypeptide hydrogel was achieved by strong segregation of the hydrophobic alkyl chains at low temperature, and the shape recovery of the deformed hydrogel was accompanied by the gradual decrease of the segregation strength with the temperature increase.     

Graft copolymers with hydrophilic and hydrophobic polyether side chains

Poly(ethylene glycol)methyl ether methacrylate (PEOMA) and oligo(propylene glycol)-4-nonylphenyl ether acrylate (OPOPhNA) were copolymerized by atom transfer radical polymerization (ATRP). Grafting through method was employed in the presence of CuBr/HMTETA or CuBr/PMDETA catalyst/ligand complex in anisole at 70 °C. It yielded a heterografted copolymers containing hydrophilic PEO and hydrophobic OPOPhNA side chains with polymerization degree DP = 68-315 in the presence of PMDETA and DP = 48-195 in the presence HMTETA. Moreover, higher reactivity of PEOMA than OPOPhNA (r_methacrylate > r_acrylate), which was observed during copolymerization, suggested the formation of copolymers with a spontaneous gradient composition starting from the grafted segment of P(PEOMA). The molecular weight distribution (MWD) was increased with DP in the range 1.2-1.6. The X-ray diffraction analysis (WAXS) indicated that larger number of PEO segments generated crystalline properties in the copolymers with amorphous OPOPhNA.     

Synthesis of terpolymers having a phospholipid polar group and poly(oxyethylene) in the side chain and their protein adsorption–resistance properties

Terpolymers having phospholipid polar groups were synthesized from 2‐methacryloyloxyethyl phosphorylcholine (MPC), methacryloyl or acryloyl poly(oxyethylene) macromonomers (POEM) [(CH₂CH₂O)_n (where n = 2–23); PEOM(2), PEOM(23), ME(9), Ph(6)], and n‐butyl methacrylate (BMA). The characteristics of these terpolymer membranes were investigated by water content (H) and X‐ray photoelectron spectroscopy. The content of water in the terpolymer increased with increasing content of MPC and length of oxyethylene units. The membranes of terpolymers were found to adsorb bovine serum albumin much less than those of poly(methyl methacrylate) and poly(BMA). Even though the contents of MPC in the terpolymer were 5 to 25 mol %, the terpolymer depressed BSA adsorption more than poly(MPC‐co‐BMA) consisting of 29 mol % of MPC. The use of terpolymer with POEM can decrease the amount of MPC in the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1092–1105, 2002     

不需预保护羟基的侧链亲水非离子水性聚氨酯的制备与性能

以酒石酸与聚乙二醇单甲醚(MPEG)为原料,在不需预保护酒石酸中羟基的情况下,经过酯化反应合成了酒石酸聚乙二醇单甲醚酯(TMPEG),以其为亲水单体通过预聚体法制备了一系列非离子型水性聚氨酯(TWPU)乳液.通过1HNMR、FTIR、拉伸测试对TMPEG和TWPU进行了结构表征与性能测试.考察了亲水单体TMPEG质量分...     

不需预保护羟基的侧链亲水非离子水性聚氨酯的制备与性能

以酒石酸与聚乙二醇单甲醚(MPEG)为原料,在不需预保护酒石酸中羟基的情况下,经过酯化反应合成了酒石酸聚乙二醇单甲醚酯(TMPEG),以其为亲水单体通过预聚体法制备了一系列非离子型水性聚氨酯(TWPU)。通过1HNMR、FTIR、TGA、拉伸测试对TMPEG和TWPU进行了结构表征与性能测试。考察了亲水单体TMPEG质量分数对TWPU贮存稳定性、力学性能、吸水率的影响。结果表明：当TMPEG质量分数为24%（以TMPEG、聚己二酸-1,4-丁二醇酯二醇、异佛尔酮二异氰酸酯、三羟甲基丙烷、乙二胺反应合成的预聚体的总质量为基准,下同）时,TWPU乳液平均粒径为85nm,TWPU胶膜接触角为84°,拉伸强度为7.9MPa,断裂伸长率为768%。     

Layered liquid-liquid flow in microchannels having selectively modified hydrophilic and hydrophobic walls

When two immiscible liquids make contact in a microchannel, the flow pattern is affected by the affinity between channel walls and liquids. In this study, microchannels (200 μm in width and 200 μm in depth) having a T-shaped bifurcation point were fabricated on PMMA plates. The inner walls of the microchannels were modified in a zone-selective manner to be either hydrophilic or hydrophobic, based on verification accomplished via a laser interference fringe technique. The microchannel was placed horizontally, and water and octane were introduced into the upper-side channel (hydrophilic) and into the lower-side channel (hydrophobic), respectively. The experimental results showed that water and octane formed a stable layered flow, and the two liquids were virtually completely separated at the T-shaped section, even when static pressure was intentionally applied to the outlets. CFD simulation, using FLUENT 6.3 software, was performed to explain the role of zone-selective modification of microchannel walls.     

Flame retardation of polyethylene: Effect of a phosphorus flame retardant having both hydrophobic and hydrophilic groups in the same molecule

The effect of phosphorylated cashew nut shell liquid prepolymer (PCNSL), a phosphorus‐based flame retardant (FR) possessing both hydrophobic and hydrophilic groups in the same molecule, on the processability, mechanical properties, thermal and flammability behavior, and aging characteristics of low‐density polyethylene (LDPE) was studied. TGA showed that PCNSL enhanced the thermal stability of LDPE, whereas limiting oxygen index (LOI) values increased from 17 to 24.5. The large increase in the LOI value could most probably be due to the possibility of PCNSL acting, apart from being a normal phosphorus‐containing FR, also as an antioxidant that might control the oxidative surface degradation of LDPE. The oxidative induction test (PE, 2.5 min, with 2% PCNSL, 225 min, and 2% Irganox®, 189 min) showed that the antioxidant property of PCNSL is better than that of Irganox®, a known antioxidant for polyethylene (PE) and the enthalpy of oxidation (PE 4.6 kJ/g, with 2% PCNSL 2.6 kJ/g and 2% Irganox®, 2.2 kJ/g) for the PCNSL/LDPE blend was less than that of LDPE and was comparable to that of the Irganox® system. Brabender Plasticorder traces of LDPE/PCNSL blends showed good processability and miscibility. The enhanced processability and miscibility between LDPE and PCNSL are attributed to the presence of the hydrophobic aliphatic segment in the FR. The SEM microstructure of the blend supported the above findings. Comparative evaluation with standard all‐aromatic FRs such as decabromodiphenyl oxide (DBDPO) and tricresyl phosphate (TCP) was carried out and the data supported the finding that FRs having both aliphatic and aromatic moieties with hydrophobic and hydrophilic characters in the same system can give better property profiles than those without these attributes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2631–2640, 2000     

Synthesis and characterization of all-conjugated diblock copolymers consisting of thiophenes with a hydrophobic alkyl and a hydrophilic alkoxy side chain

Novel thiophene-based all-conjugated block copolymers consisting of 3-hexylthiophene and 3-{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}thiophene were synthesized using the Grignard metathesis (GRIM) polymerization method in the presence of Ni(dppp)Cl₂. Favorable transfer of the catalytic site from an electron-poor precursor to an electron-rich monomer was found to produce the block copolymer. The molecular weights of the copolymers increased slightly with increasing polymerization temperature (10.1 × 10³M_n (35 °C) → 11.1 × 10³M_n (55 °C)), suggesting that transit of the catalytic site was accelerated at high temperatures. Size exclusion chromatography, UV-vis and photoluminescence spectroscopies, and cyclic voltammetry measurements confirmed that the polymers were block copolymers. The blocks were associated and organized relative to one another in adjacent chains.