Synthesis and fluorescence properties of aromatic‐aliphatic copolyamides

The aromatic‐aliphatic copolyamides were synthesized by condensation polymerization of aromatic diamine PPD (or APS, where PPD is p‐phenylene diamine and APS is aminophenyl sulfone), aliphatic diamine HDA (or EDA, where HDA is hexanediamine and EDA is ethylenediamine), and TPC (where TPC is terephthalyl chloride) with different molar ratios of aromatic diamine to aliphatic diamine. The steady‐state fluorescence of these condensed copolymers was investigated. These copolyamides exhibit strong blue‐to‐green fluorescence. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 315–321, 2005     

Preparation and self‐assembly of poly(diglycidyl maleate‐co‐stearyl methacrylate)

Poly(diglycidyl maleate‐co‐stearyl methacrylate) (P(DGMA‐co‐SMA)) with reactive epoxy groups was synthesized by reaction of poly(maleic anhydride‐co‐stearyl methacrylate) (P(MA‐co‐SMA)) and epichlorohydrin. The effect of precipitant on self‐assembly behaviors of the resultant copolymer was investigated. It was found that vesicles and nanotubule liked aggregates can be obtained through self‐assembly of P(DGMA‐co‐SMA) in THF solution using CH₃CH₂OH (EtOH) as precipitant while spheral aggregates can be obtained using H₂O as precipitant. The mechanism of the self‐assembly behavior was discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Structure–property relationships of poly(urethane urea)s with ultra‐low monol content poly(propylene glycol) soft segments. I. Influence of soft segment molecular weight and hard segment content

Structure–property relationships in poly(urethane urea)s synthesized with ultra‐low monol content poly(propylene glycol) soft segments were investigated as soft segment molecular weight (2000, 4000, and 8000 g/mol) and hard segment content (6.3 and 9.0 wt %) were varied. Morphological features such as interdomain spacing and interphase thickness were quantified and revealed with small‐angle X‐ray scattering (SAXS) and atomic force microscopy (AFM). The thermal and mechanical behavior was assessed with a dynamic mechanical analyzer (DMA) and by differential scanning calorimetry (DSC) and stress‐strain tests. Hard segment content, over the limited range studied, had little effect on the morphology and soft segment thermal and mechanical properties. The molecular weight of the soft segments had considerably more influence on the morphology and mechanical properties. Increasing soft segment molecular weight resulted in greater interdomain spacings, as shown by SAXS, and a noticeable change in the structure, as shown by AFM. Additionally, as soft segment molecular weight decreased the soft segment glass transition broadened and rose to higher temperatures. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 229–243, 2002; DOI 10.1002/app.10168     

Preparation and characterization of syndiotactic polystyrene/ethylene‐propylene copolymer blends

The reactive compatibilization of syndiotactic polystyrene (sPS)/oxazoline‐styrene copolymer (RPS)/maleic anhydride grafted ethylene‐propylene copolymer (EPR‐MA) blends is investigated in this study. First, the miscibility of sPS/RPS blends is examined by thermal analysis. The cold crystallization peak (T_cc) moved toward higher temperature with increased PRS, and, concerning enthalpy relaxation behaviors, only a single enthalpy relation peak was found in all aged samples. These results indicate that the sPS/RPS blend is miscible along the various compositions and RPS can be used in the reactive compatibilization of sPS/RPS/EPR‐MA blends. The reactive compatibilized sPS/RPS/EPR‐MA blends showed finer morphology than sPS/EPR‐MA physical blends and higher storage modulus (G') and complex viscosity (η*) when RPS contents were increased. Moreover, the impact strength of sPS/RPS/EPR‐MA increased significantly compared to sPS/EPR‐MA blend, and SEM micrographs after impact testing show that the sPS/RPS/EPR‐MA blend has better adhesion between the sPS matrix and the dispersed EPR‐MA phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2084–2091, 2002     

含氟聚合物的合成概述

概述了无定型含氟树脂、可熔性聚四氟乙烯（PFA）、热塑性氟塑料THV、聚偏氟乙烯（PVDF）等含氟聚合物新品种的性能和合成方法。     

聚醚二醇钾盐引发D．L－丙交酯的开环聚合研究

以聚乙二醇－４０００钾盐为引发剂．合成了食不同长度聚醚链段的聚Ｄ．Ｌ－乳酸－聚乙二醇－聚Ｄ．Ｌ－乳酸（ＰＬＡ－ＰＥＧ－ＰＬＡ）三嵌段共聚物。考察了溶剂用量、引发剂用量、反应温度和时间、ＰＥＧ分子量、不同溶剂对聚合反应的影响。以１Ｈ－ＮＭＲ、ＩＲ、ＤＳＣ、ＧＰＣ对共聚物进行了表征。     

Synthesis of well-defined poly(styrene)-b-poly(p-tert-butoxystyrene) multiblock copolymer from poly(alkoxyamine) macroinitiator

The stepwise insertion reaction of styrene (St) and p-tert-butoxystyrene (BOSt) into poly(alkoxyamine) macroinitiator was carried out to provide well-defined poly(St)-b-poly(BOSt) multiblock copolymers. Structural confirmation of the multiblock copolymers was accomplished by NMR and IR measurements. The model reaction also supported that the monomer insertion into the macroinitiator proceeded in accordance with a living fashion.     

Phase Behavior and Mechanical Properties of Siloxane-Urethane Copolymer

Two series of siloxane-urethane copolymers were prepared from polydimethylsiloxane (PDMS) with a molecular weight of 1000 or 1800 which was used as a soft segment, 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (1,4-BD). Differential scanning calorimetry (DSC) demonstrated that the position (T_gs) and breadth (ΔB) of soft-segment glass transition of copolymers remained constant as the hard-segment content increased. Heat capacities at soft-segment glass transition of the copolymer (ΔCp) were 0.195∼0.411 J/g^○C and heat capacities of pure PDMS (ΔCp₀) were 0.571∼0.647 J/g^○C, leading to the various ΔCp/ΔCp₀ ratios. The ΔCp/ΔCp₀ ratios decreased as the increasing of hard-segment content, showing poor phase separation. The FTIR spectrum confirmed the occurrence of hydrogen bonding in ether end-group of pure PDMS. The ether group of the soft segment led to interfacial mixing between soft and hard segments. The tan δ of the soft segment determined by dynamic mechanical testing (DMA) also identified the mixing of soft and hard segments. The mechanical properties of the copolymer were directly related to either the soft and hard segment contents or the chain lengths of soft and hard segments. The hard segment that reinforced the soft segment and interfacial thickness between soft and hard segment dominated the mechanical properties.     

Surface properties of block and graft polystyrene–polydimethylsiloxane copolymers

The surface compositions of a series of polystyrene‐b‐polydimethylsiloxane (PS‐b‐PDMS) and polystyrene‐g‐polydimethylsiloxane (PS‐g‐PDMS) copolymers were investigated using ATR‐FTIR and XPS technique. The results showed that enrichment of PDMS soft segments occurred on the surface of the block copolymers as well as on that of graft copolymers. And the magnitude order of the enrichment was as follows: PS‐b‐PDMS > PS‐g‐PDMS, which was attributed to the facilitating of the movement of the PDMS segments in PS‐b‐PDMS copolymer. Meanwhile, the solvent type and the contact medium had influence on the accumulation of PDMS on the surfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

New perfectly difunctional organolithium initiators for block copolymer synthesis: 2. Difunctional polymers of dienes and of their triblocks copolymers with styrene

New organodilithium initiators were prepared in a hydrocarbon solvent in the absence of any polar additive. Although these initiators are insoluble when they are synthesized, they may be easily purified and reacted with dienes to give perfectly telechelic polydienes having unimodal distributions and low dispersity. A good agreement between experimental and theoretical molecular weights was observed. The polymer microstructures were similar to those of polymers initiated by butyllithium in the same solvent. Triblock thermoplastic elastomers were also prepared, the characteristics of which are given. The mechanical properties of a S.B.S. sample support also the claim of a good initiating ability and difunctionality of these initiators.