Gas permeation properties of poly(2,5-dialkyl-p-phenyleneethynylene) membranes

Dipropynylbenzenes with alkyl groups (CH₃C ≡ CRC₆H₂RC≡CCH₃, R=n-C₆H₁₃, n-C₈H₁₇, n-C₁₀H₂₁, 1a–c, respectively) were polymerized with Mo(CO)₆ to afford solvent-soluble poly(2,5-dialkyl-p-phenyleneethynylene)s (2a–c). The polymers (2a–c) had high molecular weight over 3×10⁴, and gave free-standing membranes by solution casting method. According to thermogravimetric analysis (TGA), these poly(p-phenyleneethynylene)s showed high thermal stability (T₀ ≥380 °C). The densities of membranes of poly(2,5-dialkyl-p-phenyleneethynylene)s (2a–c) were 0.936–0.965, and their fractional free volume (FFV) were relatively large (ca. 0.14–0.15). The oxygen permeability coefficients (PO₂) of membranes of 2a–c were 4.88, 7.06, and 16.6 barrers, respectively.     

Synthesis and properties of new highly soluble poly(amide-ester-imide)s containing poly(ethylene glycol) as a soft segment

In this study, a new class of highly soluble poly(amide-ester-imide)s (PAEI)s contains poly(ethyleneglycol) (PEG) as hydrophilic and soft segment were prepared. Poly(ethylene glycol)-bis-(N-trimellitylimido-4-phenyl carboxylic acid) (3) as a novel diacid monomer was synthesized via two step. The reaction of poly(ethylene glycol) (PEG 6000) with trimellitic anhydride chloride yield poly(ethylene glycol)-bis-trimellitic anhydride (1). The reaction of dianhydride 1 with p-aminobenzoic acid (2) produces novel diacid monomer 3. The direct polycondensation technique of the diacid 1 with several aromatic diamines was carried out in pyridine/N-methyl-2-pyrrolidone/triphenylphosphite/CaCl₂ as condensing agent. The resulting novel PAEIs with inherent viscosities ranging between 0.21 and 0.42 dl g⁻¹, were obtained in good yield. This group of polymers exhibit excellent solubility in a variety of organic solvents and water. All of these polymers were characterized with FT-IR spectroscopy. Thermal properties, ¹H-NMR and XRD study of these PAEIs were also reported. The results demonstrate that this polymers show crystalline structure as well as high thermal stability. In addition the effect of PEG length on solubility and thermal properties of the polymers were also studied.     

Molecular-hydrodynamic study of poly(<Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="Italic">N</Emphasis>-vinylacetamide) macromolecules

High-velocity sedimentation, translational isothermal diffusion, and viscometry in H₂O and DMF are used to investigate the samples and fractions of poly(N-methyl-N-vinylacetamide) synthesized by free-radical polymerization and fractionated in a chloroform-diethyl ether system. Molecular masses M and the Mark-Kuhn-Houwink-Sakurada relations are obtained for the fractions in the molecular mass range M × 10⁻³ = 3.5−540.0. The negative temperature coefficient of intrinsic viscosity is revealed for both solvents. The length of the Kuhn statistical segment and the hydrodynamic diameter of poly(N-methyl-N-vinylacetamide) macromolecules are estimated; the hydrodynamic volumes occupied by water-soluble poly(N-methyl-N-vinylacetamide), poly(1-vinyl-2-pyrrolidone), poly(vinylformamide), and pullulan molecules are compared.     

Synthesis and gas permeability of poly(<Emphasis Type="Italic">p</Emphasis>-phenyleneethynylene)s having bulky alkoxy or alkyl groups

Dipropynylbenzene with branched alkoxy and alkyl groups [CH₃C≡CRC₆H₂RC≡CCH₃, R = 2-methylpropoxy (1a), 3-methylbutoxy (1b), 4-methylpentoxy (1c), cyclohexylmethoxy (1d), 2-ethylhexoxy (1e), 2-octoxy (1f), 2-ethylhexyl (1g), and 2-octyl (1h)] were polymerized with Mo(CO)₆ in the presence of 4-(trifluoromethyl)phenyl to afford poly(2,5-di(alkoxy or alkyl)-p-phenyleneethynylene)s (2a–h). Polymer 2a was insoluble in any solvents, but the other polymers (2b–h) were soluble in common organic solvents. The polymers with relatively long side chains (2e–h) had high molecular weight over 1.6 × 10⁴ and gave free-standing membranes by solution-casting method. The densities of membranes of 2e–h were 0.914–0.998, and their fractional-free volume values were relatively large (0.094–0.158). The oxygen permeability coefficients of membranes of 2e–h were 18.4, 12.7, 4.85, and 19.3 barrers, respectively. It was found that poly(p-phenyleneethynylene) with 2-octyl side groups, which have the branch at the nearest position from main chain, exhibited the highest gas permeability.     

Temperature dependent electrical conductivity of p-doped poly(3,4-ethylenedioxythiophene) and poly(3-alkylthiophene)s

Summary Temperature dependent electrical conductivity of substituted polythiophenes (poly(3,4-ethylenedioxythiophene) PEDOTh and head-to-tail type poly(3-alkylthiophene) HT-P3RTh) has been measured. The electrical conductivity (σ) of p-doped PEDOTh and HT-P3RTh obeys equations of a type, ln σ= ln σ_o− (T_o/T)^0.25, with the T_o value of about 10⁵–10⁷ K. Received: 21 December 1998/Revised version: 8 February 1999/Accepted: 15 February 1999     

Synthesis and properties of new poly(amide-imide)s based on 2,5-bis(trimellitimido)toluene

Summary A series of new aromatic poly(amide-imide)s were synthesized by the triphenyl phosphite activated polycondensation of the diimide-diacid, 2,5-bis(trimellitimido)toluene (I) with various aromatic diamines. The poly(amide-imide)s had inherent viscosities of 0.69–1.89 dL/g. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents. Transparent, flexible, and tough films of these polymers could be cast from DMAc or NMP solutions. Their cast films had tensile strengths ranging from 76 to 112 MPa, elongations at break from 8 to 31%, and initial moduli from 2.20 to 2.99 GPa. The glass transition temperatures of these polymers were in the range of 253–328°C. Received: 25 September 1998/Revised version: 2 December 1998/Accepted: 8 December 1998     

Synthesis and characterization of novel aromatic-aliphatic poly(amide-imide-imide)s (PAII)

Novel poly(amide-imide-imide)s (PAII) were prepared by polycondensation of a new monomer synthesized from trimellitic anhydride and glutamic acid, followed by reflux condensing with thionyl chloride and several diamines. Polymers and monomers were characterized by ¹H NMR and FT-IR spectroscopy, elemental analysis and mass spectrometry. Inherent viscosities of the resulting polymers were in the range of 17–26 mL g^–1 (M_w 13 400–29 160, polydispersity (M_w/M_n) ca. 1.3–1.7), representing rather low molecular weights. The glass transition temperatures of the polymers were in the range of 210–285°C depending on the structure of diamines, and the thermal stability of the polymers was up to 400°C, comparable with that of polyimides and poly(amide imide)s. All the polymers synthesized are well soluble in aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and dimethylacetamide. Particularly, polymers containing oxydianiline and 4,4′-diaminodiphenyl sulfone were quite soluble in m-cresol, pyridine, nitrobenzene and tetrahydrofuran.     

Synthesis of Poly(propargyl esters) with Rhodium Catalysts and Their Characterization

Summary Propargyl esters (HC≡CCH₂OC(=O)R; 1: R = n-C₅H₁₁, 2: R = CH₃, 3: R = CHBrCH₃, 4: R = C₆H₅, 5: R = C(C₆H₅)₃) were polymerized by using (nbd)Rh⁺(η⁶-Ph-B^-Ph₃) (nbd = 2,5-norbornadiene) to produce poly(1)–poly(5) with molecular weights in the range of M_n = 4,900–40,000. Poly(1), poly(3) and poly(4) were readily soluble in common organic solvents such as toluene, THF and CHCl₃, and poly(2) showed similar solubility behavior except that it was insoluble in THF. Poly(5) did not dissolve in any organic solvent. Poly(1) was yellow oil, while poly(2)–poly(5) were yellow solids. Poly(1)–poly(4) exhibited UV-vis absorptions in a range of 300–425 nm, which are attributed to the conjugation of the main chain. All the polymers were thermally stable up to 150–200 °C.     

Effects of phenyl-based pendent groups on helical conformation of poly(<Emphasis Type="Italic">N</Emphasis>-propargylamides)

Five achiral N-propargylamide monomers with various phenyl-based substitutents, [HC ≡ CCH₂NHCOR, R for M1: C₆H₄CH₃; M2: C₆H₄CH₂CH₃; M3: C₆H₄(CH₂)₂CH₃; M4: C₆H₄(CH₂)₃CH₃; M5: C₆H₄C(CH₃)₃], were synthesized and polymerized with a rhodium catalyst, (nbd)Rh⁺B^-(C₆H₅)₄ (nbd = 2,5-norbornadiene). The corresponding five homopolymers were obtained in high yields of 90–95% and with moderate molecular weights (M _n ≥ 10 000). All the polymers possessed high cis contents (≥95%). Poly(1)–poly(3) exhibited UV-vis absorption peaks at approx. 350 nm, which indicates that the three polymers formed helical conformations, while no UV-vis absorption peaks could be observed in poly(4) and poly(5) in the wavelength range of 320–500 nm, demonstrating that these two polymers could not adopt helical structures under the examined conditions. To confirm the helical structures formed in poly(1)–poly(3), a chiral monomer, M6, was utilized to copolymerize with M2, which was used as the representative for M1−M3. M6 was utilized since its polymer could form stable helices under suited conditions. The resulting copolymers exhibited remarkable CD effects, however, the maximum wavelength in the copolymers varied remarkably, mainly depending on the composition of the copolymers. It is concluded that in the formation of ordered helical conformations, the substitutents of varied bulk led to different steric repulsion and varied synergic effects among the neighboring pendent groups.     

Amine functionalization of poly(styryl)lithium with N-(benzylidene)trimethylsilylamine

Functionalization reactions of poly(styryl)lithium with N-(benzylidene)-trimethylsilylamine produce polymers containing significant amounts of coupling products for M_n = 2.8 × 10³g/mol (19% coupling) and M_n = 15 × 10³g/mol (15% coupling). Isolation and characterization of the products for the amination of poly(styryl)lithium with M_n = 2.8 × 1³g/mol indicates that the non-coupled products consist of a primary amine-terminated polymer (69% yield) and an acetophenone-type functionalized polymer (12% yield). The dimeric product (19% yield) has a primary amine functional group. The formation of these products is rationalized by a Cannizzaro-type reaction of the initially formed polymeric lithium silylamide product with excess N-(benzylidene)(trimethylsilylamine to form the corresponding polymer with imine chain-end functionality which can react with another molecule of poly(styryl)lithium to form dimer product or hydrolyze to the acetophenone functionality on work-up.     

<Emphasis Type="SmallCaps">l</Emphasis>-Aspartic acid incorporated optically active poly(amide-imide)s: synthesis and characterization

N-trimelliticimido-l-aspartic acid (1) was prepared from the reaction of trimellitic anhydride with l-aspartic acid in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The solution polycondensation of the corresponding activated monomer with eight aromatic diamines were carried out in DMAc. The resulting poly(amide-imide)s were obtained in quantitative yields, showed admirable inherent viscosities (0.20–0.36 dl g⁻¹), good optical activity (+7.32o to +15.24o), and were readily soluble in polar aprotic solvents. They start to decompose (T _10%) above 170 °C and display glass-transition temperatures at 120–237 °C. All of the above polymers were fully characterized by UV, FT–IR, and ¹HNMR spectroscopy, elemental analysis, thermogravimetric analyses, DSC, inherent viscosity measurement, and specific rotation.     

Synthesis and Properties of Novel Poly(p-phenylenevinylene)s Containing a Tricarbonyl(arene)chromium Unit in the Main Chain

Summary Novel π-conjugated polymers based on poly(p-phenylenevinylene)s (PPVs) containing a tricarbonyl(arene)chromium unit in the main chain were synthesized by Horner-Wadsworth-Emmons olefination. The structures of the polymers were supported by ^lH NMR and IR spectra. The polymers obtained were soluble in common solvents such as THF, CH₂Cl₂, CHCl₃ and toluene. The molecular weights of the polymers were determined by GPC. Their thermal, optical, and electrochemical properties were investigated in detail. Received: 18 November 2002/Revised version: 10 February 2003/ Accepted: 11 February 2003 Correspondence to Yoshiki Chujo     

Imide-to-benzoxazole rearrangement in ortho substituted poly(4-4'-diphenylene pyromellitimide)s

Summary Ortho substituted poly(4,4'-diphenylene pyromellitimide)s were prepared from pyromellitic dianhydride and 3,3′-dihydroxybenzidine or 3,3′-dimethoxybenzidine. Thermal cyclodehydration of the corresponding poly(amic acid)s, PAA, led to the formation of ortho-hydroxy- or o-methoxy-polyimides, while catalytic imidization in the presence of aliphatic anhydrides was accompanied by acylation of the OH groups resulting in the formation of lateral acetoxy substituents. The direction of the latter reaction was controlled by the acidity of dehydration agents and the use of a catalyst. Imidization in the presence of acetic anhydride and pyridine led to poly[(3,3'-diacetoxy-4,4'-diphenylene)pyromellitimide] and the use of trifluoroacetic anhydride resulted in the formation of the corresponding polyisoimide with ortho-trifluoroacetoxy groups. This polyisoimide was completely soluble in amide solvents above 60°C. The polymers were studied by FTIR spectroscopy, TGA, and WAXS. It was found that ortho substituents such as OH and methoxy groups could react with the imide cycle above 350°C causing its rearrangement to benzoxazole. The formation of notable amounts of benzoxazole was also observed for o-acetoxy polyimides. Received: 20 November 2001/Revised version: 19 March 2002/ Accepted: 19 March 2002     

Silylated poly(4-hydroxystyrene)s as negative electron beam resists

Silylated poly(4-hydroxystyrene)s and radical polymerized 4-tert-butyldimethylsilyloxystyrene (TBDMSOSt) were examined as electron beam resists. Commercial poly(4-hydroxystyrene) (PHS) with M_w = 1.69 × 10⁴ and M_w/M_n = 5.41 was silylated with 1-(trimethylsilyl)imidazole and tert-butylchlorodimethylsilane. Both silylation reactions proceeded quantitatively to afford trimethylsilylated PHS with M_w = 3.93 × 10⁴ and M_w/M_n = 4.91, and tert-butyldimethylsilylated PHS with M_w = 4.08 × 10⁴ and M_w/M_n = 3.81. These 2 silyl ether polymers acted as a negative working resist to electron beam (EB) exposure. Sensitivity and contrast of tert- butyldimethylsilylated PHS were not affected by prebake temperature around its T_g of 97°C, while those of PHS were dependent on prebake temperature around its T_g of 160°C. At a prebake temperature of 125°C, the sensitivity parameter and the contrast γ value were obtained as follows: 3.93 × 10⁻⁴ C cm⁻² and 0.91 for PHS; 1.49 × 10⁻⁴ C cm⁻² and 1.06 for trimethylsilylated PHS; 1.84 × 10⁻⁴ C cm⁻² and 1.44 for tert-butyldimethylsilylated PHS. The silylation procedures obviously improved the sensitivity of PHS. TBDMSOSt was polymerized in bulk at 60°C with 2,2′-azobisisobutyronitrile (AIBN) as an initiator. The resultant poly(TBDMSOSt) possessed M_w = 3.01 × 10⁵ and M_w/M_n = 1.92 and exhibited a sensitivity of 1.60 × 10⁻⁵ C cm⁻² and a γ value of 1.47. More than 10 times enhancement of sensitivity was observed compared with tert-butyldimethylsilylated PHS. Such a high sensitivity is probably due to the high molecular weight of the bulk polymerized material. Poly(TBDMSOSt) resolved an isolated line of 0.20 μm width and 0.5 μm line and space patterns. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1151–1157, 1998     

A new class of poly(1,6-heptadiyne)-based photorefractive materials by metathesis polymerization

SUMMARY: We utilized the first metathesis reaction to synthesize a new type of photorefractive polymers that contain both a carbazole moiety as a hole transporter and NLO chromophores. These polymers have a long tail band at above 700 nm, indicating the formation of intramolecular charge transfer complexes between the carbazole groups and the conjugated double bonds in the polymer backbone. Also, these polymers show two maximum values of photocurrent around 350 and 700 nm. The electro-optic coefficient (r ₃₃) at the wavelength of 1.3 μm for polymer thin films poled around the 85°C were in the range of 1.6 ∼6.3 pm/V. The hyperpolarizabilities, <γ>, of the resulting polymers were ca. 2.9 × 10⁻³² esu. at the incident wavelength of 1.907 μm. Received: 1 June 1998/Revised version: 27 July 1998/Accepted: 5 August 1998     

Intrinsic viscosity-number average molecular weight relationship for poly (n-Octadecyl acrylate) and poly (N-n-octadecylacrylamide)

Intrinsic viscosity-number average molecular weight relationships have been measured, at 30C in benzene, for poly (n-octadecyl acrylate) as [η]=2.72×10⁻⁴ Mn^0.638 and for poly (N-n-octadecylacrylamide) as [η]=0.82×10⁻⁴ Mn^0.676. Whole polymers of various molecular weights were prepared in benzene solution at 65C with dodecyl mercaptan as primary regulator. By the use of these parameters, the molecular weight of such polymers and their homologs may now be measured by simple solution-viscosity determinations. In the expression { } (relating degrees of polymerization { } to the mercaptan/monomer ratio), intercept { } and apparent transfer constant C_s for n-octadecyl acrylate were 6.28×10⁻³ and 0.68; for N-n-octadecylacrylamide 1.10×10⁻³ and 0.62 respectively. These parameters permit preparation of homopolymers of chosen molecular weight. Presented at the AOCS Meeting, Philadelphia, October 1966 E. Utiliz. Res. Devel. Div., ARS, USDA.     

Optical application of poly(HEMA-<Emphasis Type="Italic">co</Emphasis>-MMA) containing silver nanoparticles and N,N-dimethylacrylamide

High functional ophthalmic lens materials, poly(HEMA-co-MMA)s, were prepared by the copolymerization of HEMA, MMA, NVP, EDGMA, and N,N-dimethylacrylamide in the presence of silver nanoparticles. Silver nanoparticles have antimicrobial properties and a hydrophilic monomer N,N-dimethylacrylamide has excellent biocompatibility and oxygen transmissibility. The water content was in the range of 36.63–44.45%, indicating the characteristics of general water-content contact lenses, and the refractive index was measured to be in the range of 1.423–1.435. Meanwhile, the oxygen transmissibility ranged from 10.63×10⁻¹¹ to 18.85×10⁻¹¹ (cm²/sec)(mlO₂/ml×mmHg) increasing with increasing the addition ratio of N,N-dimethylacrylamide. The polymeric materials satisfied the basic characteristics required for ophthalmic contact lenses. The polymers can be used to fabricate antimicrobial hydrogel contact lenses with high oxygen transmissibility.     

A novel π-conjugated polymer : poly(3,4-bis(phenylene)-3-cyclobutene-1,2-dione)

We have investigated a new 1,2-type aromatic dibromide monomer for preparing a modified π -conjugated poly(p-phenylenevinylene). A novel π -conjugated poly(p-phenylenevinylene) was prepared by dehalogenation polycondensation of a dibromoaromatic compound with a squaric unit as a monomer with zerovalent nickel [Ni(0)] complex. The monomer and the polymer were characterized by FT-IR, ¹H-NMR, Elemental Anaylsis, TGA, DSC, GPC and UV-Visible. The resultant polymer had good solubility to polar aprotic, solvents, e.g. DMF, DMAc, DMSO and NMP and solvatochromism in DMAc. Received: 17 July 1998/Revised version: 14 December 1998/Accepted: 15 December 1998     

Synthesis and properties of poly(amide-imide)s based on 1,5-bis(4-trimellitimido)naphthalene

1,5-Bis(4-trimellitimido)naphthalene (II) was prepared by the condensation reaction of 1,5-naphthalenediamine and trimellitic anhydride. A series of aromatic poly(amide-imide)s (IV _a–o) was synthesized by the direct polycondensation of the diimide-diacid (II) and various aromatic diamines (III _a–o). The reaction utilized triphenyl phosphite and pyridine as condensing agents in the presence of calcium chloride in N-methyl-2-pyrrolidone (NMP). The inherent viscosities of the resulting poly(amide-imide)s were in the range of 0.55∼1.39 dL/g. These polymers were generally soluble in polar solvents, such as N,N-dimethylacetamide (DMAc), NMP, N,N-dimethylformamide (DMF). Flexible and tough poly(amide-imide) films were obtained by casting from a DMAc solution and had tensile strengths of 90∼145 MPa, elongations to break of 5∼13 %, and initial moduli of 2.29∼3.73 GPa. The glass transition temperatures of some poly(amide-imide)s were recorded in the range of 206∼218 °C, and most of the polymers did not show discernible glass transition on their DSC traces. The 10% weight loss temperatures were above 522 °C in nitrogen and above 474 °C in air atmosphere.     

Ring-opening polymerization of (CH3)2Si[CpMo(CO)3]2, a molecule with an –Si(CH3)2– bridge between two cyclopentadienyl ligands

The (CH₃)₂Si[CpMo(CO)₃]₂ complex (1) was synthesized and used to explore ring-opening polymerization (ROP) as a method to prepare high molecular weight polymers containing Mo–Mo bonds along their backbones. Attempts to initiate ROP of 1 using n-BuLi or PtCl₂ did not yield any polymers. The X-ray crystal structure of 1 shows that the Si center is not strained, and it is suggested that no ROP occurred because 1 is less strained than other organometallic ROP monomers, such as the silicon-bridged ferrocenophanes. Thermal ROP (TROP) of 1 was successful and yielded a polymer (M _w = 210,000 g mol⁻¹) containing both Mo–Mo single bonds and Mo≡Mo triple bonds. When CO_(g) is passed over the polymer in the solid state, the Mo≡Mo triple bonds are converted to Mo–Mo single bonds. Attempts to increase the yield of the TROP polymer by increasing the reaction times led to polymer decomposition. The decomposition is likely caused by the weakness of the Mo–Mo bond, cleavage of which causes the polymer to degrade.