Low-temperature Solution Polymerization Research Articles

Soluble polyarylate with high thermal stability and low-k at high frequency

• A novel semi-fluorinated polyarylate based on phenolphthalein (CPAR-F) was successfully synthesized. • The introduction of fluorine atoms into the molecular chain can effectively reduce the dielectric constant of the polymer. • CPAR-F has excellent thermal stability with T 5d reaching 473 °C under nitrogen. • The good solubility of CPAR-F allows it to be cast into thin films by solution processing. To obtain high thermally stable and low dielectric materials, a semi-fluorinated polyarylate (CPAR-F) based on phenolphthalein and tetrafluoroterephthalic chloride is synthesized via a facile low temperature solution polymerization. CPAR-F is demonstrated to have excellent heat resistance with 5% weight loss temperature (T 5d ) at 473 °C and high glass transition temperature (300 °C), as well as high solubility and mechanical properties. In particularly, CPAR-F possesses low dielectric constant of 2.5 at a high frequency of 10 GHz, good hydrophobicity and low water uptake, indicating this CPAR-F exhibits potential applications for fabrication of devices used in 5G communication.

Synthesis and characterization of processable aromatic poly(ether ether ketone amide)s modified by phenoxy and 1,3 ketone moiety linkages

New series of aromatic poly(ether ether ketone amide)s were synthesized by low-temperature solution polymerization of novel aromatic diamine, namely 1,3-bis-4′-(4″-aminophenoxy benzoyl)benzene (XIV), and aromatic diacid chlorides, viz. isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC). Co-poly(ether ether ketone amide)s were also synthesized by employing various mole proportions of IPC and TPC with diamine (XIV). These poly(ether ether ketone amide)s were characterized by FTIR, solubility, inherent viscosity, TGA, DSC, and XRD. Inherent viscosities of these poly(ether ether ketone amide)s were in the range of 0.41–0.52 dL/g in DMAc, indicating the formation of moderate to high molecular weight of polymers. Poly(ether ether ketone amide)s showed good solubility in polar aprotic solvents such as N,N-dimethyl acetamide (DMAc), N-methyl 2-pyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide. These poly(ether ether ketone amide)s had glass transition temperatures, as determined by DSC, in the range of 252–302 °C. These polymers showed similar decomposition patterns and had no weight loss below 335 °C, and temperatures for 10% weight loss (T10) were in the range of 397–406 °C, indicating that these polymers showed good thermal stability.

Synthesis and properties of semi-crystalline poly(decamethylene terephthalamide) thermosets from reactive side-group copolyamides

We have prepared semi-crystalline polyamide (PA) thermosets using reactive side-group functionalized copolyamides as precursors. Reactive meta- and para-based phenylethynyl diacid chlorides (IPE and TPE) were synthesized and incorporated in poly(decamethylene terephthalamide) (PA 10T) using a low temperature solution polymerization method. The phenylethynyl-based comonomers disrupt crystallization of the final copolyamides and lower the onset of melting. Copolyamides containing 5, 10 and 15 mol% of the reactive comonomer could be cured at 350 °C into freestanding PA thermoset films. All thermoset films are stable up to 400 °C, as confirmed by DMTA, which is the result of network formation. The thermosets exhibit both a crystalline phase and a crosslinked amorphous phase. Depending on the concentration of the side-groups, the degree of crystallinity of the final thermosets can be controlled and suppressed by 52–76% compared to the PA 10T reference polymer. Most notable is the fact that the IPE-15 thermoset film exhibits outstanding stress–strain behavior, i.e. elongation at break (∼17%) and toughness (766 MJ·m−3).

Preparation and gas transport properties of thermally induced rigid membranes of copolyimide containing cardo moieties

The diamine monomer with ortho-hydroxyl groups and fluorene moiety, 9,9-bis (3-amino-4-hydroxyphenyl)fluorene (BisAHPF), was prepared. The 6FDA-FDA-BisAHPF copoly(amic acid) (PAA) solution was synthesized from the diamines 9,9-bis(4-aminophenyl)fluorene (FDA), BisAHPF and aromatic dianhydride 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) by a low-temperature solution polymerization. The thernally treated PAA films were used as precursor to prepare thermally induced rigid membranes in N2 and air atmosphere at the temperature range of 300–480°C, respectively. The thermally induced rigid membranes included thermal oxidative membranes and thermally rearrangement (TR) membranes. Their physical and chemical properties were characterized by FTIR, XPS, XRD, DSC and TGA. Single gas permeation performances of thermally induced rigid membranes were studied for five representative gases of interest including H2, O2, N2, CO2, and CH4. Highly gas permeability were obtained after the thermal treatment. Therefore, the introduction of “cardo” moieties helped to improve the gas permeability. In addition, a proper thermal treatment could tune to the gas separation performance of the thermally induced rigid membrane materials

Synthesis and thermal properties of polyhydroxyamide copolymer and its derivatives

We synthesized a polyhydroxyamide (PHA) copolymer via low-temperature solution polymerization of 3,3'-dihydroxybenzidine with terephthaloyl chloride (80.0 mol%) and isophthaloyl chloride (20.0 mol%) in N,Ndimethylacetamide with the aid of LiCl. We prepared the PHA copolymer derivatives containing the fluorine-based substituents and investigated their solubility, cyclization behavior, and thermal properties using a differential scanning calorimeter (DSC), a thermogravimetric analyzer (TGA), and the simultaneous thermogravimetric analyzer coupled with a mass spectrometer (STA-MS). The chemical structures of the PHA copolymer and its derivatives, as well as the polybenzoxazoles (PBOs) obtained through thermal cyclization of the copolymer and derivatives, were determined by a fourier transform infrared (FT-IR) spectroscopic analysis. The PHA copolymer could be dissolved in organic solvents only with the aid of LiCl, while its derivatives were readily soluble in DMAc and NMP without LiCl at room temperature. The DSC and TGA results demonstrated that the PHA copolymer derivatives could be converted to PBOs at a lower temperature than the PHA copolymer.

Thermal Cycloimidization Study of Polyimides and Poly(amide imide)s Synthesized from Low-Temperature Solution Polymerization

Polyimides (PI)s and Poly(amide imide)s (PAI)s containing di/tri-structural arrangements of monomer constituents were synthesized from 1,2,4,5 benzenetetracarboxylic anhydride/3,3′,4,4′ benzophenonetetracarboxylic dianhydride, diamines and trimellitic dianhydride chloride, i.e., a mixture of dianhydrides and diamines, using low-temperature solution polymerization. The majority of the resulting polymers were readily soluble in polar aprotic solvents such as dimethylformamide, dimethylsulfoxide, dimethylacetamide, etc. Thermal cycloimidization studies by thermogravimetic analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR) revealed that the rate of cycloimidization was much faster during the initial 15 min, and then occurred at much slower rates till the completion. The activation energies (Ea) for thermal cycloimidization of poly(amic acid)s was calculated from the rate of mass loss of the polymer heated at different temperatures according to the Coats and Redfern method. PI and PAIs derived from diamines containing single cyclic/benzene ring structures, such as m-phenylenediamine and 1,3-cyclohexanebis(methylamine), showed less amount of char yield than those having two benzene rings and separated by methylene, sulfone, or ether linkages. The structure of both diamine and trimellitic chloride had a profound effect on the polymer chain mobility, as indicated by the big variation in the glass transition temperatures. Thermally stable polymers were developed into membranes and tested for their mechanical strength by dynamic mechanical analysis(DMA).

Preparation of novel poly(amide-sulfonamide) (PASA) and its application in 2,4-dinitrophenol adsorption

In the search for new materials to separate 2,4-dinitrophenol (DNP) from 2,4-dinitroanisole (DNAN), we have focused on the polymer design and synthesis of novel porous poly(amide-sulfonamide) (PASA) containing both repeated amide and sulfonamide functional groups from the reaction of m-chlorosulfonylbenzoyl chloride with 4,4′-diamino diphenyl sulfone in DMAc, using low-temperature solution polymerization. The structure and thermal property of the PASA were characterized by BET, SEM, FT-IR, 1H NMR, XRD, TGA; the selective removal of 2,4-DNP from DNAN solution was analysed by adsorption experiments. The BET, SEM and XRD results showed that the PASA with a porous morphology is nearly amorphous; the molecular weight of the polymer was investigated by GPC. Thermogravimetric analysis indicated that the reasonably high temperature recorded (>380 °C) before a 5% weight loss occurred. The removal rate of 2,4-DNP solution was 54.11% at 30 °C.

방향족 폴리히드록시아미드의 합성과 열적 고리화 거동(II) -플루오르 치환체의 영향-

Polyhydroxyamide (PHA) was synthesized via low-temperature solution polymerization of 3,3'-dihydroxybenzidine with isophthaloyl chloride, and the derivatives of PHA containing fluoro-substituents were investigated for exploring their potential application as new thermally stable polymer material. The structural properties, solubility, and thermal cyclization of the PHA and its derivatives were characterized using FT-IR, DSC, and TGA to derive the relationship between the structure of the PHA derivatives and the thermal properties and cyclization behavior of the polymer. The PHA derivatives containing fluoro-substituents were readily soluble in a variety of solvents without LiCl, whereas the pristine PHA was soluble only in the presence of LiCl. The DSC analyses under isothermal conditions showed that the PHA derivatives exhibited a faster cyclization rate than the pristine PHA at <TEX>$220^{\circ}C$</TEX> and <TEX>$250^{\circ}C$</TEX>. In addition, the DSC and TGA results revealed that the PHA derivatives could be cyclized into the corresponding polybenzoxazoles at lower temperatures than the pristine PHA; this could be attributed to the lower thermal activation energy of the derivatives owing to the introduction of the fluoro-substituents.

폴리히드록시아미드 섬유의 제조와 열처리에 따른 구조-물성 상관관계(I) -다양한 고화조건에 따른 고화거동-

Abstract: Polyhydroxyamide (PHA) was synthesized using low temperature solution polymerization of 3,3'-dihydrox-ybenzidine (DHB) and isophthaloyl chloride (IPC) in N,N-dimethylacetamide (DMAc). In order to study wet-spinningof PHA fibers, the diffusion property of DMAc in various coagulants and the effect of coagulation bath temperaturewere evaluated. The initial diffusion rate of DMAc, and the SEM images and mechanical properties of PHA fibers,demonstrated that the coagulation in ethanol at 20 o C was the most optimal among all the conditions examined. Thetensile strength and initial modulus of PHA fibers increased, while its breaking strain decreased with increasing spindraw ratio (SDR). The wide-angle X-ray diffraction (WAXD) experiment revealed that the crystallinity of PHA fibersincreased with increasing SDR. The process-structure-property relationship among PHA fibers under various coagula-tion conditions was also investigated. Keywords: PHA fibers, spinning dope, coagulation bath temperature, coagulants, initial diffusion rate, spin draw ratio

Preparation, characterization and thermal degradation study of poly(amide imide)s based on tri-component mixture of PMDA/BTDA, diamines and acid chloride

A series of poly(amide imide)s (PAIs) having alternate (amide–amide) and (imide–imide) units (polymers 1–14 and 22–35), and random distribution of amide-imide linkages (polymers 15–21 and 36–42) were prepared by low temperature solution polymerization of benzene-1,2,4,5-tetracarboxylic dianhydride (PMDA)/benzophenone-3,3′,4,4′-tetracarboxylic dianhydride (BTDA), diamines (cyclic and aromatic) and acid chloride in dimethylforamide. All the polymers were readily soluble in polar aprotic solvents with inherent viscosities in the range of 0.134–0.878. The process of cycloimidization of poly(amide amic acid)s (PAAs) to PAIs was investigated by TGA and FT-IR techniques at four different temperatures i.e., 175, 200, 225, and 260 °C. The rate of cycloimidization was calculated by taking into account the theoretical weight loss (WT), obtained from [n × Mw (H2O)/Mw (RU)] W, where Mw (H2O) molecular weight of water, W weight of PAA taken for TGA, Mw (RU) the molecular weight of repeat unit of PAA, n number of water molecules eliminated per repeat unit of PAA upon cycloimidization. For a particular diamine, the extent of percentage cycloimidization at the end of the isothermal heating was higher for PAAs containing trimellitic anhydride chloride (TMAc) unit, irrespective of the nature of the dianhydride and diamine. Thermal and thermooxidative degradation of PAIs was investigated by TGA in nitrogen and oxygen atmosphere. The initial decomposition temperatures (IDT) of polymers are above 260 °C, and vary widely (from 260 to 501 °C) depending upon the structure of the polymer backbone. PAIs containing TMAc exhibited higher thermal stability as compared to those polymers having diacid chloride units, in both N2/O2 atmospheres.

방향족 폴리히드록시아미드의 합성과 열적 고리화 거동(I) -벤젠고리 치환구조의 영향-

We have synthesized polyhydroxyamides (PHAs), a possible precursor which could be converted to polybenzoxazole (PBO) through a thermal cyclization reaction, by low temperature solution polymerization of 3,3`-dihydroxybenzidine with terephthaloyl chloride or isophthaloyl acid. Structural characteristics, solubility, thermal cyclization, and thermal decomposition of the PHAs were investigated by the FT-IR, DSC and TGA in order to understand the effect of chemical structure of acyl chlorides on the thermal properties of PHAs. The FT-IR study reveals that two types of PHAs can cyclize on heating and be transformed into PBOs. The meta-type PHA (m-PHA) shows better solubility in N,N-dimethylformamide and dimethyl sulfoxide than the para-type PHA (m-PHA). DSC and TGA results demonstrate that the m-PHA can cyclize at lower temperature than p-PHA, which is due to the difference in activation energy of thermal cyclization between m-PHA and p-PHA. TGA results reveal that the p-PHA has better thermal stability than m-PHA while in flame.

Research Progress on Preparation Methods of PMIA Fiber

PMIA is a functional fiber with superior heat-resistance, flame resistance, high temperature dimensional stability and electrical insulation. In PMIA crystal structure, there exist hydrogen bonds between two planes in the crystal and they are arranged in grid. The strong interactions between hydrogen bonds result in a very stable chemical structure of PMIA. Owing to lower internal rotation potential energy than PPTA, PMIA molecular chains are flexible structures and its elastic modulus is in the same level as other flexible macromolecules. In this paper, the structure character of molecular chain and performance of PMIA have been introduced. Additionally, the common used polymerization techniques for PMIA have been described in detail. These synthesis techniques include low-temperature solution polymerization, interfacial polymerization and emulsion polymerization.

Synthesis and characterization of novel aromatic–aliphatic polyamides from bis-[(4-aminobenzyl)-4-benzamide] ether

Abstract A novel aromatic diamine monomer containing preformed aromatic–aliphatic amide and ether linkage, bis-[(4-aminobenzyl)-4-benzamide] ether (BABE) was prepared from 2-phenylacetonitrile. BABE was characterized by FT-IR, 1H NMR, 13C NMR and mass spectrometry. Five new aromatic polyamides were prepared by low temperature solution polymerization from BABE and different mole proportions of isophthaloyl chloride (IPC) or terephthaloyl chloride (TPC). The resulting polymers were characterized by means of FT-IR, inherent viscosity [ηinh], solubility, differential scanning calorimetry [DSC], thermogravimetric analysis [TGA] and X-ray diffraction [XRD]. Polyamides were obtained in good yields and had moderate to high molecular weights as indicated by inherent viscosities in the range 0.63–1.35 dL/g in (DMAc + 4% LiCl). XRD results showed the partly crystalline nature of polymers and these polymers dissolved in aprotic polar solvents containing LiCl. The solubility of copolyamides improved due to random placement of constituent IPC and TPC during polymerization. DSC analysis of these polyamides showed glass transition temperatures in the range of 197–204 °C, and they showed no weight loss below 336 °C when analyzed by TG. These polyamides have potential applications as engineering materials.

Synthesis and Characterization of Poly(hydroxyamide-benzoxazole) Multi-Block Copolymers

Poly(hydroxyamide-benzoxazole) multi-block copolymers were prepared from the polymerization of 2,2′-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (6FAP) and 4,4′-oxydibenzoyl chloride (ODBC). N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) or N,O-bis(trimethylsilyl)acetamide (BSA) was used as a silylation agent to activate amine functional groups. The amine terminated hydroxyamide prepolymers (ATHA) were synthesized by employing the low temperature solution polymerization via the in situ silylation method. p-Toluenesulfonic acid was added into the reaction mixture of ATHA, which in turn followed by cyclodehydration at 150 ∼ 190°C 4 for 24 hrs to produce amine terminated benzoxazole oligomers (ATBO). Finally, the poly(hydroxyamide-benzoxazole) multi-block copolymers were prepared from the condensation of ATHA, ATBO and ODBC by employing the silylation method at relatively low temperature of 60°C. In the present work, properties of multi-block copolymers have been investigated.

Properties, characterization and preparation of halogenated aromatic polyamides

This paper describes certain wholly aromatic polyamides based on 1,3-diamino-4-halobenzenes and 1,3-diamino-4,6-dihalobenzenes, and on isophthaloyl and terephthaloyl chloride by means of low temperature solution polymerization. We set out to study the influence of the kind of halogen (F, Cl or Br) and the type of substitution (mono or di) in the diamine moiety with regard to solubility, water uptake and thermal and mechanical properties. The materials are characterized with respect to chemical structure and purity by elemental analysis, infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic techniques, and special attention is paid to the sequence distribution (constitutional order) of polymers derived from non-symmetric monohalogen-substituted diamines, and their influence on the above-mentioned properties.

Linear and Branched Architectures from the Polymerization of Lactide with Glycidol

Samples of polylactide (PLA) were synthesized by initiating lactide ring opening with glycidol using Sn(Oct)2 catalyst. Under low-temperature solution polymerization conditions, epoxide ring opening is precluded, leading to predominately linear epoxide capped PLA. With high-temperature bulk polymerization, simultaneous lactide and epoxide ring opening leads to hyperbranched polyesters characterized by linear PLA segments separating glycerol branch points. Molecular weights and extent of branching were determined by gel permeation chromatography (GPC), and the presence of branching was confirmed by solution viscosity measurements and g‘ calculations. Solution polymerizations yielded linear samples with controlled number-average molecular weights in the range 4800−19 200 g/mol. Number-average molecular weights of branched samples from bulk polymerization ranged from 19 800 to 100 800 g/mol. The branched samples exhibited relatively low polydispersity indices (PDI) in the range 1.48−2.00. Glass transition te...

Synthesis, characterization and thermal properties of soluble aromatic poly(amide imide)s

Novel diamines such as N, N′-bis(aminoaryl)terephthalamido-2-carboxylic acids (BATCA), which contain primary amine, amide and carboxylic acid groups and are soluble in dilute aqueous NaOH solution, were synthesized by reacting aromatic diamines with trimellitic anhydride chloride in dimethylformamide. Poly(amide imide)s containing 3:1 ratio of amide:imide groups in the polymer chain were prepared by low temperature solution polymerization of BATCAs with isophthaloyl chloride or terephthaloyl chloride in dimethylformamide at 5–10 °C to form poly(amide amic acid)s, and followed by treating with a mixture of triethylamine and acetic anhydride. The PAIs were soluble in polar aprotic solvents like dimethylformamide, dimethylacetamide, dimethylsulphoxide and N-methylpyrrolidone, and have inherent viscosities in the range of 0.30–0.66 dL/g. The PAIs were characterized by IR, 1H NMR and 13C NMR techniques. Thermogravimetric analysis (TGA) has shown that the initial decomposition temperatures of the polymers are in the range of 250–440 °C, depending upon the structures of diamine and diacid chloride. The glass transition temperatures of the PAIs are in the range of 128–320 °C. The IDT and T g values of the polymers containing terephthaloyl unit are higher by about 20–40 °C than those of the polymers with isophthaloyl unit. BATCA could be utilized for the preparation of thin film composite membranes having PAA/PAI barrier layer on PES by in situ interfacial polymerization with IPC/TPC/TMC.

Preparation of high-molecular-weight poly(N-vinylcarbazole) by the photoinduced low-temperature solution polymerization ofN-vinylcarbazole in 1,1,2,2-tetrachloroethane

For the preparation of high-molecular-weight (HMW) poly(N-vinylcarbazole) (PVCZ) with a narrow molecular weight distribution, N-vinylcarbazole (VCZ) was solution-polymerized in 1,1,2,2-tetrachloroethane (TCE) at −20, 0, and 20°C with photoinitiation. The effects of the polymerization temperature and the concentrations of the polymerization solvent and photoinitiator on the polymerization behavior and molecular parameters of PVCZ were investigated. A low polymerization temperature with photoirradiation was successful in obtaining HMW PVCZ with a smaller temperature rise during polymerization than that for thermal free-radical polymerization by azobisisobutyronitrile (AIBN). The photo-solution-polymerization rate of VCZ in TCE was proportional to [AIBN]0.45. The molecular weight was higher and the molecular weight distribution was narrower for PVCZ made at lower temperatures. For PVCZ prepared in TCE at −20°C with a photoinitiator concentration of 0.00003 mol/mol of VCZ, a weight-average molecular weight of 920,000 was obtained, with a polydispersity index of 1.46, and the degree of transparency converged to about 99%. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2391–2396, 2003

Characterizations of poly(vinyl pivalate) polymerized in tertiary butyl alcohol and resulting syndiotactic poly(vinyl alcohol) microfibrils saponified

Vinyl pivalate (VPi) was solution-polymerized in tertiary butyl alcohol (TBA) and in dimethyl sulfoxide (DMSO) with low chain transfer constant using a low temperature initiator, 2,2′-azobis(2,4-dimethylvaleronitrile) (ADMVN). TBA was absolutely superior to DMSO in increasing the syndiotacticity and molecular weight of poly(vinyl alcohol) (PVA). Low-temperature solution polymerization of VPi in TBA or DMSO by adopting ADMVN proved to be successful in obtaining PVA of ultrahigh molecular weight (maximum number-average degree of polymerization (Pn): 13,500–17,000) and of high yield (ultimate conversion of VPi into PVPi: 55–80%) to a much higher conversion than that from bulk polymerization. Moreover, PVA from TBA system were fibrous, with a high degree of orientation of the crystallites, indicating the syndiotactic nature of TBA polymerization.

Thermal cyclization of the poly(amic acid): thermal, mechanical, and morphological properties

Poly(amic acid) (PAA) was obtained by means of low-temperature solution polymerization of benzidine and pyromellitic dianhydride (PMDA). PAA exhibits a large endothermic peak between 110°C and 250°C, with a peak temperature around 164°C. This is attributed to the loss of water during the conversion of PAA to polyimide (PI). With increasing thermal cyclization temperatures from 25°C to 200°C, these endothermic peaks decrease drastically from 213.8 to 0.4 J/g. The endothermic peak finally became unobservable in the DSC thermogram for the heat treated sample at 250°C, due to the fully thermal heterocyclization. All the before- and after-heat-treated precursor films show a good thermal stability and a high weight residue % at 900°C in the range of 46–64%. The tensile strength and initial modulus of the precursor were 103 MPa and 5.40 GPa, respectively, and then gradually increased up to 178 MPa and 12.13 GPa with increasing thermal cyclization conditions. From SEM, we can see that the particle shape of the precursor changes from an irregular shape to a tetragonal crystalline phase with thermal cyclization above 150°C. This is due to the extension and crystallization of the rigid PI chain. The degree of crystallinity was determined to be between 1% and 43% with increasing thermal cyclization conditions. PAA showed a good solubility in strong acid as well as in aprotic solvents, such as DMAc, NMP, and DMSO, but heat-treated samples at higher temperatures showed a poor solubility in the same solvents.