聚酰胺6-聚氨酯嵌段共聚物的合成及表征

以聚醚三元醇、二苯甲烷二异氰酸酯以及己内酰胺为单体,在碱性催化剂条件下,通过单体浇铸工艺合成聚酰胺6-聚氨酯(PA6-PU)嵌段共聚物.采用傅里叶变换红外光谱仪、差示扫描量热仪表征其结构与性能.结果表明,PA 6-PU嵌段共聚物的熔点下降,且具有两相结构.力学性能分析显示,PU组分的嵌入使共聚物的常温冲击强度南7.20 kJ/m2提高到42.76 kJ/m2,低温(-50℃)冲击强度由4.20 kJ/m2提高到15.14 kJ/m2.     

Adhesive properties of ABA poly(styrene-b-isoprene) block copolymers

ABA poly(styrene-b-isoprene) block copolymers with various molecular weight and elastomeric content were used as heat activated adhesives. The shear strength of glass to glass joints was tested. The influence of activation temperature and ageing on shear strength was also examined. Good adhesive and cohesive behaviour was found for copolymers with low total molecular weight and identical block lengths. These results were explained by the fact that phase separation does not easily occur in such copolymers.     

Synthesis of acetophenone formaldehyde resin containing ABA type block copolymers by ATRP

Well‐defined ABA type block copolymers of acetophenone formaldehyde resin (AFR) and methyl methacrylate (MMA) were synthesized via atom transfer radical polymerization. In the first step, acetophenone formaldehyde resin containing hydroxyl groups was modified with 2‐bromopropionyl bromide. Resulting difunctional macroinitiator was used in the ATRP of MMA using copper bromide (CuBr)/N,N,N′,N″,N″‐pentamethyl‐diethylenetriamine (PMDETA) as the catalyst system at 90°C. The chemical composition and structure of the copolymers were characterized by nuclear magnetic resonance (¹H‐NMR) spectroscopy, Fourier transform infrared (FT‐IR) spectroscopy, and molecular weight measurement. Gel permeation chromatography (GPC) was used to study the molecular weight distributions of the AFR block copolymers. M_n up to 24,000 associated with narrow molecular weight distributions (PDI < 1.5) were obtained with conversions up to 79%. Coating properties of obtained block copolymers such as adhesion and reflectance values were investigated. They showed good adhesion properties on Plexiglass substrates. Reflectance values increased as the resin content of polymer increased. The thermal properties of all polymers were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All block copolymers showed higher thermal stability than their precursor AFR resin. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and properties of poly(imide siloxane) block copolymers with different block lengths

Several poly(imide siloxane) block copolymers with the same bis(γ‐aminopropyl)polydimethylsiloxane (APPS) content were prepared. The polyimide hard block was composed of 4,4′‐oxydianiline and 3,3′,4,4′‐diphenylthioether dianhydride (TDPA), and the polysiloxane soft block was composed of APPS and TDPA. The length of polysiloxane soft block increased simultaneously with increasing the length of polyimide hard block. For better understanding the structure–property relations, the corresponding randomly segmented poly(imide siloxane) copolymer was also prepared. These copolymers were characterized by FT‐IR, ¹H‐NMR, dynamic mechanical thermal analysis, thermogravimetric analysis, polarized optical microscope, rheology and tensile test. Two glass transition temperatures (T_g) were found in the randomly segmented copolymer, while three T_gs were found in the block copolymers. In addition, the T_gs, storage modulus, tensile modulus, solubility, elastic recovery, surface morphology and complex viscosity of the copolymers varied regularly with increasing the lengths of both blocks. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and bulk properties of poly(tetrahydrofuran)-poly(2-methyl-2-oxazoline) ABA triblock copolymers

A series of linear triblock-copolymers of the ABA type in which the central B-block is poly(tetrahydrofuran) (polyTHF) and the A-segments are poly(2-methyl-2-oxazoline) (polyMeOX) were synthesized by a one-pot sequential monomer addition copolymerization, utilizing the living nature of the cationic ring-opening polymerization of both monomers. Films of the copolymers, casted from chloroform solutions, exhibit excellent mechanical properties in comparison with the homopolymers with comparable molecular weights, which was ascribed to the phase separation occurring between the two copolymer segments. Materials, in which the polyTHF B-segment have a molecular weight 13 000 g/mol or higher and each polyMeOX A-block a molecular weight 1500 g/mol, kept elastomeric properties up to 130 °C notwithstanding the fact that this temperature is considerably higher than the melting point of polyTHF and the glass transition temperature of polyMeOX. It was found that these triblock-copolymer materials show a shape memory effect. These observations are attributed to the high degree of phase separation between the two blocks and the strong polar interactions between the polyMeOX segments. Received: 20 March 1997/Revised: 5 September 1997/Accepted: 8 September 1997     

Synthesis and properties of amphiphilic thermo-sensitive block copolymers

Octadecyl acrylate (ODA) as hydrophobic monomer and N-isopropylacryamide (NIPAAm) as hydrophilic monomer were chosen to synthetize the thermo-sensitive block copolymers PODA_x-PNIPAAm_y-PODA_x (BAB-type) via reversible-addition-fragmentation chain transfer (RAFT) polymerization, the block copolymers could self-assemble to flower-like micelles in aqueous solution with hydrophobic PODA as the inner core and stabilized by hydrophilic PNIPAAm as the outer shell. The characterizations of the micelles such as surfactivity, thermo-sensitivity, micelle hydrodynamic radius (R _h ) and polydispersity index (PdI) were demonstrated by surface tension technique, UV-Vis, and dynamic light scattering (DLS) measurements, respectively. The longer the hydrophilic chain was, the higher the critical micellization concentration (CMC) would be, and the higher content of the PODA was, the lower the lower critical solution temperature (LCST) would be. The average R _h remained at about 100 nm below LCST, but decreased sharply to about 42 nm and kept constant when reaching and above LCST, which meant the non-aggregation of BAB type block copolymers. The micelle was homogeneous with the small PdI within the range of research. B_0.5mA_24mB_0.5m had the largest capacity to encapsulate lipophilic Sudan Red IV model drugs and the drug loading efficiency was 9.76%.     

含端基氯低聚物引发剂的合成及其引发苯乙烯聚合的研究

通过对４种端羟基低聚物进行氯乙酰化反应,制备了一系列含端基氯的低聚物,然后以这些含端基氯的低聚物为大分子引发剂,在ＣｕＣｌ／ｂｐｙ存在下引发苯乙烯的ＡＴＲＰ反应,得到ＡＢＡ嵌段共聚物。用＾１Ｈ－ＮＭＲ分析证明了聚合物的嵌段结构,以ＳＥＣ测定了聚合物的相对分子质量及其分布,发现嵌段聚合物的相对分子质量和单体转化率成正比,并和相对分子质量的理论值Ｍ↑－ｎ,ｔｈ＝（Δ［Ｍ］／［ｏｌｉｇｏｍｅｒ－Ｃｌ］）     

Synthesis of block copolymers of poly(p-dioxanone) block poly(tetrahydrofuran)

Summary The triblock copolymers of poly(p-dioxanone)-b-poly(tetrahydrofuran)-b-poly(p-dioxanone) were synthesized by ring-opening polymerization of p-dioxanone in the presence of dihydroxyl poly(tetrahydrofuran)(PTHF) using stannous octoate (SnOct₂) as a catalyst. The effects of feed ratio, reaction time and reaction temperature on the copolymerization were investigated. It was found that the optimal reaction temperature and time were 80 °C and 42 hours, respectively, and the molar ratio of p-dioxanone/SnOct₂ (PDO/cat.) had little influence on the inherent viscosity of the copolymers. The triblock copolymers were characterized by various analytical techniques such as ¹H-NMR and DSC.     

Solvation and phase separation in ABA block copolymers

A conceptual scheme is presented for classifying the phase behavior of ABA block copolymers and solvents. The effect of solvent fraction ?_S on microphase separation is described for macroscopically homogeneous systems, but more attention is focused on the limits of solubility. A “miscibility map” is developed in terms of solubility parameters δ_A, δ_B, and δ_S and used to define regions of macrophase separation, complete miscibility, and partial miscibility. Combined with known triblock molecular structure, the miscibility map can be used to predict the character of solvated systems and guide the selection of solvents for special purposes. A survey of reports in the literature shows qualitative consistency with this treatment. New observations are reported on solvation of a polystyrene–polybutadiene–polystyrene polymer in numerous solvents; these are used to infer microstructural information and define the miscibility map more realistically.     

Synthesis and solution properties of poly(acrylamide-styrene) block copolymers with high hydrophobic content

Hydrophobically associating block copolymers of polyacrylamide/styrene with a high hydrophobe content were synthesized using micellar copolymerization under various conditions of surfactant and initiator concentrations with the objective of determining the conditions that produce optimum solution properties for enhanced oil recovery. Solubilities, aqueous solution viscosities and interfacial properties with air and oil of the copolymers were investigated. The influence of salt on the solution properties was also studied. Nature of hydrophobic sites and onset of hydrophobic association were studied by measuring the fluorescence of pyrene in polymer solutions. Optimum solution properties were obtained for copolymers synthesized under conditions of high surfactant and initiator concentrations. The copolymers displayed substantial thickening properties at low concentrations with enhanced thickening in the presence of salt. The interfacial tensions of the aqueous solutions with n-decane and air were also reduced. Interfacial properties were slightly sensitive to salt concentration. The copolymer solutions showed shear and temperature thinning behaviors typical of polymer solutions.     

Synthesis of novel block copolymers containing polyamide4 segments and control of their biodegradability

Different novel copolymers, ABA‐type block copolymers composed of polyamide4 as outer segments and polyoxyethylene as an inner segment and AB‐ and ABA‐type block copolyamides containing polyamide4 and another hydrophilic polyamide derived from a bicyclic lactam, were synthesized by the anionic ring‐opening polymerization of 2‐pyrrolidone using the corresponding acyllactam‐type macromolecular activators. The degradation rate of both block copolymers containing polyamide4 segments in a composted soil was found to decrease with increasing content of the second segments, although they were also hydrophilic and/or biodegradable. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3492–3498, 2004     

Synthesis of ABA block Co-Oligomers of polymethylmethacrylate and poly (dimethylsiloxane)

A methoxysilyl macromonomer containing an acrylic chain is obtained by telomerization of methyl methacrylate with mercaptopropylmethyldimethoxysilane. This macromonomer is then reacted with a polydimethylsiloxane hydroxytelechelic leading to new block Co-Oligomers with acrylic and siloxane moieties.     

Structural characterization and thermal behaviour of block copolymers of polydimethylsiloxane and polyamide having trichlorogermyl pendant groups

Block copolymers having a pendant trichlorogermyl group as a part of polyamide segment? (CO? R′? CO? NH? Ar? NH? )_xCO? R′? CO? and polydimethylsiloxane of general formula [(? CO? R′? CO? HN? Ar? NH)_x? CO? R′? CO? NH(CH₂)₃SiO(CH₃)₂ ((CH₃)₂SiO)_ySi(CH₃)₂(CH₂)₃ NH? ]_n (where R′ = CH₂CH(GeCl₃), CH(CH₃)CH(GeCl₃), CH(GeCl₃)CH(CH₃); Ar = C₆H₄, (? C₆H₃? CH₃)₂, (? C₆H₃? OCH₃)₂, 2,5‐(CH₃)₂? C₆H₂, C₆H₄? O? C₆H₄) were prepared by a polycondensation reaction and characterized using CHN and Ge analysis, Fourier transform infrared (FTIR) and ¹H NMR spectroscopy, thermogravimetric analysis (TGA) and molecular weight determination. They have a lamellar structure with weight‐average molecular weight in the range 1.21 × 10⁵–4.79 × 10⁵ g mol^?1. These copolymers display two glass transition temperatures and have an average decomposition temperature of 489 °C. TGA, FTIR and gas chromatography/mass spectrometry studies indicate that degradation of these block copolymers results in carbon monoxide, oligomeric siloxanes and polyamide fragments. They are thermally stable due to the hydrogen bonded interlinked chains of polyamide, while they absorb water due to the presence of Ge? Cl bonding. Copyright © 2010 Society of Chemical Industry     

Synthesis and properties of monomer casting polyamide 6/poly(methyl methacrylate) blends

We successfully synthesized monomer casting polyamide 6 (MCPA6)/poly(methyl methacrylate) (PMMA) blends in two steps: (1) radical polymerization of methyl methacrylate in ?‐caprolactam and (2) anionic ring‐opening polymerization of this ?‐caprolactam solution. The influence of PMMA on the crystallization behavior of MCPA6 was studied with differential scanning calorimetry and X‐ray diffraction, which showed that PMMA could act as a heterogeneous nucleation agent and favored the formation of the γ‐crystalline form. The rheological properties were also studied and indicated that PMMA reduced the interaction between MCPA6 chains by lowering the density of hydrogen bonding. This study used a novel and convenient method to prepare microporous MCPA6/PMMA particles that involved removing the continuous phase. Their surface area and thermal stability were characterized by the Brunauer–Emmett–Teller method and thermogravimetric analysis, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis by reactive processing of block copolymers of Nylon 6 / Poly (ether-esteramide)

Summary Block copolymers of nylon 6 with 10, 15 and 20% of poly (ether-esteramide) as elastomeric phase were synthesized by reactive processing. These materials are obtained by the anionic polymerization of -caprolactam in the presence of a linear prepolymer of poly (ether-esteramide) with a Grignard reagent. Differential Scanning Calorimetry (DSC), torque rheometry and formic acid test were used to characterize the obtained copolymers. The results showed that block copolymers of Nylon 6 were formed. The melting temperature and the crystallinity of the copolymer decreased when the elastomer phase content increased. Two Tgs appeared; the blocks of the copolymers were not miscible. We calculate the size of nylon 6 blocks for each composition. The physical-mechanical behavior was also studied. More flexible materials were obtained when the soft phase content in the copolymer was increased. The results of this work provide an important information for the synthesis of this kind of materials by reactive extrusion.     

苯乙烯-丁二烯-苯乙烯-甲基丙烯酸酯嵌段共聚物的合成与表征

用正丁基锂为引发剂,环已烷和四氢呋喃为混合溶剂,以苯乙烯、丁二烯、甲基丙烯酸酯为单体,按阴离子顺序加料方法合成了聚苯乙烯-丁二烯-苯乙烯-甲基丙烯酸酯嵌段共聚物,共聚物经GPC、IR、DSC、TEM等测试方法表征。结果表明,在30 ℃左右、1,1-二苯基乙烯(DPE)戴帽和LiCl配合的条件下,合成了窄分布(MWD<1.3)聚苯乙烯-丁二烯-苯乙烯-甲基丙烯酸酯嵌段共聚物,成功地在SBS中引入了一小段极性链段。     

Semifluorinated ABA triblock copolymers: Synthesis,characterization, and amphiphilic properties

In this study a series of novel semifluorinated ABA triblock copolymers with different fluorinated segment lengths and different fluorocarbon side‐chain structures were synthesized via atom transfer radical polymerization (ATRP) and macroinitiator techniques. The macroinitiator, telechelic bromine terminated polystyrene, was obtained from bulk ATRP of styrene with α,α′‐dibromo‐p‐xylene as the initiator and cuprous bromide/α,α′‐bispyridine complex as the catalyst. The polymerization reactions of 2‐[(perfluorononenyl)oxy] ethyl methacrylate and ethylene glycol monomethacrylate monoperfluorooctanoate were initiated by the macroinitiator in the presence of additional catalyst. The characterization of the block copolymers was performed by gel permeation chromatography, ¹H‐NMR spectroscopy, and differential scanning calorimetry. The surface activities of the block copolymers in toluene were investigated with the Wilhelmy plate method. The solid surface energy of the block copolymers was determined by measurement of the contact angles. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2625–2633, 2002     

丙烯腈-丙烯酰胺共聚物的合成与热性能研究

采用溶液自由基法制备了丙烯腈(AN)-丙烯酰胺(AM)共聚物,采用傅立叶变换红外光谱(FTIR)、核磁共振光谱(NMR)、差示扫描量热仪(BSC)和热重分析(TG)等方法对聚合产物进行了表征。研究结果表明,随着AM的加入,共聚物的分子质量和转化率都具有先增大后减小的变化趋势。AN的质量分数为2%(w)时,分子质量和转化率最高,且共聚单体AM能在较低温度时以离子机理形式引发聚丙烯腈(PAN)原丝的氧化、环化放热反应并能减缓放热效应。     

Effect of center block structure on the physical and rheological properties of ABA block copolymers. Part II. Rheological properties

The effect of the chemical structure of the center block on the rheological properties of ABA block copolymers with polystyrene end blocks has been investigated. The chemical structure of the center blocks investigated in the present paper are polybutadiene, polyisoprene, ethylene/butene copolymer, ethylene/propylene copolymer and polydimethyl-siloxane. The chemical structure of the center block was found to have a pronounced effect on the rheological properties of the ABA block copolymer melts. The long range relaxation times of these block copolymer melts increases with increasing incompatibility between the styrene block and the center block. However, the rheological properties of the block copolymers are not influenced significantly by the glass transition or the entanglement molecular weight of the center block.