Synthesis and characterization of degradable copoly(ester–amide)s: Poly(trans‐4‐hydroxy‐L‐proline‐co‐ε‐caprolactam)

Novel copolyesteramides were synthesized by reacting trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline (N‐CBz‐Hpr) with ε‐caprolactam (CLM) in the presence of stannous octoate [Sn(II) Oct.] as a catalyst. Various techniques, including ¹H‐NMR, IR, DSC, and viscosity, were used to elucidate structural characteristics and thermal properties of the resulting copolymers. Data showed that the optimal reaction condition for the synthesis of the copolymers was obtained by using 3 wt % Sn(II) Oct. at 170°C for 24 h. The DSC analysis demonstrated amorphous structure for most of the copolymers. The glass‐transition temperature of the copolymers shifts to a higher temperature with increasing Hpr/CLM molar ratio. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐CLM)s was evaluated by weight loss measurements. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1615–1621, 2002     

Shape memory effect of poly(methylene‐1,3‐cyclopentane) and its copolymer with polyethylene

Poly(methylene‐1,3‐cyclopentane) (PMCP) cyclopolymerized from 1,5‐hexadiene by metallocene catalyst, rac‐(ethylenebis(1‐indenyl))Zr(N(CH₃)₂)₂ is partially crystalline and has a value of elongation at break of more than 400% in the temperature range 25–85 °C. The shape memory effect of PMCP with moderate molecular weight is enhanced by sequentially polymerized polyethylene segments, the crystalline phase of which seems to strengthen the fixed structure which memorizes the original shape. The glass transition temperature or melting temperature of PMCP can be selectively used as shape recovery temperature when an appropriate deformation temperature is chosen. © 2002 Society of Chemical Industry     

Synthesis and photo‐ and biodegradabilities of poly[(hydroxybutyrate‐co‐hydroxyvalerate)‐ g‐phenyl vinyl ketone]

The graft copolymer, poly[(hydroxybutyrate‐co‐hydroxyvalerate)‐g‐phenyl vinyl ketone] [P(HBV‐g‐PVK)], was synthesized by graft polymerization of phenyl vinyl ketone (PVK) onto poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) under nitrogen atmosphere using benzoyl peroxide. The structure of P(HBV‐g‐PVK) was identified by Fourier transform IR and ¹H‐NMR spectra. The effects of weight ratio of PVK to PHBV in feed, initiator concentration, reaction time, and reaction temperature on the grafting ratio and grafting efficiency were investigated. The thermal decomposition temperature of P(HBV‐g‐PVK) was 272°C. The tensile strengths of P(HBV‐g‐PVK) after photo‐ or biodegradation were significantly decreased due to degradation by UV irradiation or Aspergillus niger. The value of color difference (ΔE) of P(HBV‐g‐PVK) was greater than that of PHBV. The film surfaces of P(HBV‐g‐PVK) treated with UV irradiation and Aspergillus niger showed many pits as compared with the untreated P(HBV‐g‐PVK). It has been found that the photo‐ and biodegradabilities of P(HBV‐g‐PVK) was excellent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1432–1439, 1999     

Dynamic mechanical properties of polystyrene‐block‐poly[ethylene‐co‐(ethylene‐propylene)]‐block‐polystyrene triblock copolymer/hydrocarbon oil blends

Blend systems of polystyrene‐block‐poly(ethylene‐co‐(ethylene‐propylene))‐block‐polystyrene (SEEPS) triblock copolymer with three types of hydrocarbon oil of different molecular weight were prepared. The E″ curves as a function of temperature exhibited two peaks; one peak at low temperature (? ?50°C), arising from the glass transition of the poly[ethylene‐co‐(ethylene‐propylene)] (PEEP) phase and a high temperature peak (? 100°C), arising from the glass transition of the polystyrene (PS) phase. The glass transition temperature (T_g) of the PEEP phase shifted to lower temperature with increasing oil content. The shifted T_g depended on the types of oil and was lower for the low molecular weight oil. The T_g of PS phase of the present blend system, were found to be constant and independent of the oil content, when molecular weight of the oil is high. However, for the lower molecular weight oil, the T_g of the PS phase also shifted to lower temperatures. This fact indicates that the oil of high molecular weight is merely dissolved in the PS phase. The E′ at (75°C, at which temperature both of PEEP and PS phases are in glassy state, was found to be independent of oil content. In contrast, at 25°C, at which temperature the PEEP phase is in rubbery state, the E′ decreased sharply with increasing oil content. This result indicates that the hydrocarbon oil was a selective solvent in the PEEP phase. It mainly dissolved in the PEEP phase, although slightly dissolved into the PS phase as well, when molecular weight of oil is low. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of new polyureas derived from 4‐(4′‐Methoxyphenyl)urazole

4‐(4′‐Methoxyphenyl)urazole (MPU) was prepared from 4‐methoxybenzoic acid in five steps. The reaction of monomer MPU with n‐isopropylisocyanate was performed at room temperature in N,N‐dimethylformamide solution, and the resulting bis‐urea derivative was obtained in high yield and was finally used as a model for polymerization reaction. The step‐growth polymerization reactions of monomer MPU with hexamethylene diioscyanate, isophorone diioscyanate, and toluene‐2,4‐diioscyanate were performed in N,N‐dimethylacetamide solution in the presence of pyridine as a catalyst. The resulting novel polyureas have an inherent viscosity (η_inh) in a range of 0.07–0.21 dL/g in DMF and sulfuric acid at 25°C. These polyureas were characterized by IR, ¹H‐NMR, elemental analysis, and TGA. Some physical properties and structural characterization of these novel polyureas are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1141–1146, 2002     

Poly(pent‐1‐ene) Synthesized with the Syndiospecific Catalyst i‐Pr(Cp)(9‐Flu)ZrCl2/MAO

1‐Pentene was polymerized with the syndiospecific catalyst system i‐PrC(Cp)(9‐fluorenyl)ZrCl₂/MAO. The molar mass of the resulting polymers depends strongly on the reaction temperature and decreases from M̄_w = 126 000 at 0°C to M̄_w = 46 000 at 100°C, but is more or less independent of the monomer and the MAO concentration. The influence of reaction temperature and concentrations of MAO and monomer on the type of end‐groups generated during the chain termination, as well as on the type of stereoerror, was investigated. The degree of tacticity was dependent on the polymerization temperature with [rrrr] > 0.99 at 0°C and [rrrr] = 0.75 at 100°C.     

Synthesis and characterization of poly(ether ketone ketone) (PEKK)/sodium sulfonated poly(arylene ether ketone) (S‐PAEK) block copolymers

A series of well‐defined poly(ether ketone ketone) (PEKK)/sodium sulfonated poly(aryl ether ketone) (S‐PAEK) block copolymers of high molecular weights was prepared by direct nucleophilic polymerization of hydroquinone with sodium 5,5′‐carbonylbis(2‐fluorobenzene sulfonate) ( 1 ) and PEKK oligomer ( 2 ). Varying the ratio of 1 to 2 used in polymerization can be used to control the degree of polymer sulfonation, which correspondingly affects the polymer solubility in solvents. Increasing content of 1 in the copolymers, slightly decreases their thermal stability which is nevertheless thermally stable up to 400 °C. Two T_g values, or one broad T_g, were observed in the DSC measurements of the block copolymers, indicating the existence of phase separation, which was further proved by phase‐separated morphologies as shown in atomic force microscopy images. © 2001 Society of Chemical Industry     

Synthesis and properties of poly(aryl ether sulfone ether ketone ketone) (PESEKK)

4,4′‐bis(Phenoxy)diphenyl sulfone (DPODPS) was synthesized by reaction of phenol with bis(4‐chlorophenyl) sulfone in tetramethylene sulfone in the presence of NaOH. Two poly(aryl ether sulfone ether ketone ketone)s (PESKKs) with high molecular weight were prepared by low temperature solution polycondensation of DPODPS and terephthaloyl chloride (TPC) or isophthaloyl chloride (IPC), respectively, in 1,2‐dichloroethane and in the presence of aluminum chloride (AlCl₃) and N‐methylpyrrolidone (NMP). The resulting polymers were characterized by various analytical techniques, such as FT‐IR, ¹H‐NMR, DSC, TG, and WAXD. The results show that the T_g and T_d of PESEKKs are much higher, but its T_m is lower than those of PEKK. The other results indicate that PESEKKs exhibit excellent thermostabilities at 300 ± 10°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 489–493, 2005     

Synthesis,characterization and thermal degradation of poly[2‐(3‐p‐bromophenyl‐3‐methylcyclobutyl)‐2‐hydroxyethylmethacrylate]

In this work, 2‐(3‐p‐bromophenyl‐3‐methylcyclobutyl)‐2‐hydroxyethylmethacrylate (BPHEMA) [monomer] was synthesized by the addition of methacrylic acid to 1‐epoxyethyl‐3‐bromophenyl‐3‐methyl cyclobutane. The monomer and poly(BPHEMA) were characterized by FT‐IR and [¹H] and [¹³C]NMR. Average molecular weight, glass transition temperature, solubility parameter, and density of the polymer were also determined. Thermal degradation of poly[BPHEMA] was studied by thermogravimetry (TG), FT‐IR. Programmed heating was carried out at 10 °C min⁻¹ from room temperature to 500 °C. The partially degraded polymer was examined by FT‐IR spectroscopy. The degradation products were identified by using FT‐IR, [¹H] and [¹³C]NMR and GC‐MS techniques. Depolymerization is the main reaction in thermal degradation of the polymer up to about 300 °C. Percentage of the monomer in CRF (Cold Ring Fraction) was estimated at 33% in the peak area of the GC curve. Intramolecular cyclization and cyclic anhydride type structures were observed at temperatures above 300 °C. The liquid products of the degradation, formation of anhydride ring structures and mechanism of degradation are discussed. © 1999 Society of Chemical Industry     

Thermal properties and crystalline structure of liquid crystalline poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate)

Thermal properties and crystalline structure of liquid crystalline (LC) poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate) [copoly(ET/CPT)] were investigated using differential scanning calorimetry (DSC), thermogravimetry (TGA), limiting oxygen index (LOI) measurement, electron dispersive X‐ray analysis (EDX), X‐ray diffractometry, and infrared spectrometry (IR). The thermal transition temperatures of copoly(ET/CPT) were changed with the composition. Copoly(ET/CPT) showed two thermal decomposition steps and the residues at 700°C and LOI values of copoly(ET/CPT) were almost proportional to its chlorine content. The activation energy of thermal decomposition of LC units was very low compared to that of poly(ethylene terephthalate)(PET) units. Crystal structure of copoly(ET/CPT) (20/80) was of triclinic system with the lattice constants of a = 9.98 A?, b = 8.78 A?, c = 12.93 A?, α = 97.4°, β = 96.1°, and γ = 90.8°, which is very close to that of poly(chloro‐p‐phenylene terephthlate) (PCPT) with the lattice constants of a = 9.51 A?, b = 8.61 A?, c = 12.73 A?, α = 96.8°, β = 95.4°, and γ = 90.8°. When copoly(ET/CPT)(50/50) was annealed at 220°C in vacuum, crystallization induced sequential reordering (CISR) was not observed but the heat of fusion was slightly increased due to the increase of the trans isomer content in PET units. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1286–1294, 2002; DOI 10.1002/app.10451     

N‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl] phthalimide: 2. Detailed study of the monomer cure and properties of the resulting polymer

A detailed study is presented of the high‐temperature cure of the difunctional monomer N‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl]phthalimide (BPP) and the thermal properties of the resulting homopolymer. Although the phenylethynyl groups are consumed within 1 h at 370 °C, other reactions continue well after this, leading to a cured polymer whose glass transition temperature (T_g) is highly dependent on cure time and temperature. A T_g of 450 °C is achieved after a 16 h cure at 400 °C. Use of chemometrics to analyse the infrared spectra of curing BPP provides evidence for changes in the aromatic moieties during cure, perhaps indicative of co‐reaction between the biphenylene and phenylethynyl groups; however, other processes also contribute to the overall complex cure mechanism. Despite the high T_g values, BPP homopolymer exhibits unacceptably poor thermo‐oxidative stability at 370 °C, showing a weight loss of about 50 % after 100 h ageing. This is perhaps a result of formation of degradatively unstable crosslink structures during elevated‐temperature cure. Copyright © 2004 Society of Chemical Industry     

Synthesis,Crystal Structure,and Thermal Behaviors of 3‐Nitro‐1,5‐bis(4,4′‐dimethylazide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP)

The energetic material, 3‐nitro‐1,5‐bis(4,4′‐dimethyl azide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP), was firstly synthesized by means of Click Chemistry using 1,5‐diazido‐3‐nitrazapentane as main material. The structure of NDTAP was confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy; mass spectrometry, and elemental analysis. The crystal structure of NDTAP was determined by X‐ray diffraction. It belongs to monoclinic system, space group C2/c with crystal parameters a=1.7285(8) nm, b=0.6061(3) nm, c=1.6712(8) nm, β=104.846(8)°, V=1.6924(13) nm³, Z=8, μ=0.109 mm⁻¹, F(000)=752, and D_c=1.422 g cm⁻³. The thermal behavior and non‐isothermal decomposition kinetics of NDTAP were studied with DSC and TG‐DTG methods. The self‐accelerating decomposition temperature and critical temperature of thermal explosion are 195.5 and 208.2 °C, respectively. NDTAP presents good thermal stability and is insensitive.     

Synthesis of novel azo‐containing polyureas derived from 4‐[4′‐(2‐hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione

4‐[4′‐(2‐Hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione ( HNAPTD ) ( 1 ) has been reacted with excess amount of n‐propylisocyanate in DMF (N,N‐dimethylformamide) solution at room temperature. The reaction proceeded with high yield, and involved reaction of both N? H of the urazole group. The resulting bis‐urea derivative 2 was characterized by IR, ¹H‐NMR, elemental analysis, UV‐Vis spectra, and it was finally used as a model compound for the polymerization reaction. Solution polycondensation reactions of monomer 1 with Hexamethylene diisocyanate ( HMDI ) and isophorone diisocyanate ( IPDI ) were performed in DMF in the presence of pyridine as a catalyst and lead to the formation of novel aliphatic azo‐containing polyurea dyes, which are soluble in polar solvents. The polymerization reaction with tolylene‐2,4‐diisocyanate ( TDI ) gave novel aromatic polyurea dye, which is insoluble in most organic solvents. These novel polyureas have inherent viscosities in a range of 0.15–0.22 g dL^?1 in DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3177–3183, 2001     

Synthesis and properties of polyamides based on 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐hexahydro‐4,7‐methanoindan

A new diamine 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐hexahydro‐4,7‐methanoindan ( 3 ) was prepared through the nucleophilic displacement of 5,5′‐bis(4‐hydroxylphenyl)‐hexahydro‐4,7‐methanoindan ( 1 ) with p‐halonitrobenzene in the presence of K₂CO₃ in N,N‐dimethylformamide (DMF), followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new polyamides were synthesized by the direct polycondensation of diamine 3 with various aromatic dicarboxylic acids. The polymers were obtained in quantitative yields with inherent viscosities of 0.76–1.02 dl g⁻¹. All the polymers were soluble in aprotic dipolar solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidone (NMP), and could be solution cast into transparent, flexible and tough films. The glass transition temperatures of the polyamides were in the range 245–282 °C; their 10% weight loss temperatures were above 468 °C in nitrogen and above 465 °C in air. © 2000 Society of Chemical Industry     

Synthesis and properties of copolymers of poly(ether ketone ketone) and poly(ether amide ether amide ether ketone ketone)

Poly(aryl ether ketone)s (PAEKs) are a class of high‐performance engineering thermoplastics known for their excellent combination of chemical, physical and mechanical properties, and the synthesis of semicrystalline PAEKs with increased glass transition temperatures (T_g) is of much interest. In the work reported, a series of novel copolymers of poly(ether ketone ketone) (PEKK) and poly(ether amide ether amide ether ketone ketone) were synthesized by electrophilic solution polycondensation of terephthaloyl chloride with a mixture of diphenyl ether and N,N′‐bis(4‐phenoxybenzoyl)‐4,4′‐diaminodiphenyl ether (BPBDAE) under mild conditions. The copolymers obtained were characterized using various physicochemical techniques. The copolymers with 10–35 mol% BPBDAE are semicrystalline and have markedly increased T_g over commercially available poly(ether ether ketone) and PEKK due to the incorporation of amide linkages in the main chain. The copolymers with 30–35 mol% BPBDAE not only have high T_g of 178–186 °C, but also moderate melting temperatures of 335–339 °C, having good potential for melt processing. The copolymers with 30–35 mol% BPBDAE have tensile strengths of 102.4–103.8 MPa, Young's moduli of 2.33–2.45 GPa and elongations at break of 11.7–13.2%, and exhibit high thermal stability and good resistance to organic solvents. Copyright © 2010 Society of Chemical Industry     

Thermogravimetric analysis of poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)

The thermal degradation of poly(3‐hydroxybutyrate) (PHB) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [P(HB‐HV)] was studied using thermogravimetry (TG). In the thermal degradation of PHB, the temperature at the onset of weight loss (T_o) was derived by T_o = 0.97B + 259, where B represents the heating rate (°C/min). The temperature at which the weight loss rate was maximum (T_p) was T_p = 1.07B + 273, and the final temperature (T_f) at which degradation was completed was T_f = 1.10B + 280. The percentage of the weight loss at temperature T_p (C_p) was 69 ± 1% whereas the percentage of the weight loss at temperature T_f (C_f) was 96 ± 1%. In the thermal degradation of P(HB‐HV) (7:3), T_o = 0.98B + 262, T_p = 1.00B + 278, and T_f = 1.12B + 285. The values of C_p and C_f were 62 ± 7 and 93 ± 1%, respectively. The derivative thermogravimetric (DTG) curves of PHB confirmed only one weight loss step change because the polymer mainly consisted of the HB monomer only. The DTG curves of P(HB‐HV), however, suggested multiple weight loss step changes; this was probably due to the different evaporation rates of the two monomers. The incorporation of 10 and 30 mol % of the HV component into the polyester increased the various thermal temperatures (T_o, T_p, andT_f) by 7–12°C (measured at B = 20°C/min). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2237–2244, 2001     

Polymerization of acrylonitrile catalyzed by single yttrium tris(2,6‐di‐tert‐butyl‐4‐methyl phenolate)

Polymerization of acrylonitrile was carried out using yttrium tris(2,6‐di‐tert‐butyl 4‐methyl‐phenolate) (Y(OAr)₃) as single component catalyst for the first time. The effects of concentrations of the monomer and catalyst, kinds of rare earth element and solvent, as well as temperature and polymerization time were investigated. The overall activation energy of polymerization in n‐hexane and THF mixture is 18.3 kJ mol^?1. Polyacrylonitriles (PANs) obtained by using Y(OAr)₃ in n‐hexane and THF mixture at 50 °C are predominantly atactic, while yellow PANs obtained in DMF under the same conditions have a syndiotactic‐rich configuration (>50%), and their highly branched and/or cyclized structures have also been found. © 2002 Society of Chemical Industry     

Synthesis and characterization of soluble poly(arylene ether ketone)s with high glass transition temperature based on 3,6‐bi(4‐fluorobenzoyl)‐N‐alkylcarbazole

3,6‐bi(4‐fluorobenzoyl)‐N‐methylcarbazole and 3,6‐bi(4‐fluorobenzoyl)‐N‐ethylcarbazole were synthesized and used to prepare poly(arylene ether ketone)s (PAEKs) with high glass transition temperatures (T_g) and good solubility. High molecular weight amorphous PAEKs were prepared from these two difluoroketones with hydroquinone, phenolphthalein, 9,9‐bis(4‐hydroxyphenyl)fluorene and 4‐(4‐hydroxylphenyl)‐2,3‐phthalazin‐1‐one, respectively. All these polymers presented high thermal stability with glass transition temperatures being in the range 239–303 °C and a 5% thermal weight loss temperature above 460 °C. Compared with the T_g of phenolphthalein‐based PAEK (PEK‐C), fluorene‐based PAEK (BFEK) and phthalazinone‐based PAEK (DPEK) not containing a carbazole unit, these polymers presented a 30–50 °C increase in T_g. Meanwhile, PAEKs prepared from N‐ethylcarbazole difluoroketone showed good solubility in ordinary organic solvents, and all polymers exhibited excellent resistance to hydrochloric acid (36.5 wt%) and sodium hydroxide (50 wt%) solutions. In particular, phthalazinone‐based PAEK bearing N‐ethylcarbazole afforded simultaneously a T_g of 301 °C with good solubility. Tensile tests of films showed that these polymers have desirable mechanical properties. The carbazole‐based difluoroketones play an important role in preparing soluble PAEKs with high T_g by coordinating the relationship between chain rigidity resulting from the carbazole unit and chain distance from the side alkyl. © 2014 Society of Chemical Industry     

Synthesis and characterization of ternary‐copolymer of soluble fluorinated polyimides based on 1,4‐bis (4‐amino‐2‐trifluoromethylphenoxy) benzene

A series of novel ternary‐copolymer of fluorinated polyimides (PIs) were prepared from 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene (pBATB), commercially available aromatic dianhydrides, and aromatic diamines via a conventional two‐step thermal or chemical imidization method. The structures of all the obtained PIs were characterized with FTIR, ¹H‐NMR, and element analysis. Besides, the solubility, thermal stability, mechanical properties, and moisture uptakes of the PIs were investigated. The weight‐average molecular weight (M_w) and the number‐average molecular weight (M_n) of the PIs were determined using gel‐permeation chromatography (GPC). The PIs were readily dissolved not only in polar solvents such as DMF, DMAc, and NMP, but also in some common organic solvents, such as acetic ester, chloroform, and acetone. The glass transition temperatures of these PIs ranged from 201 to 234°C and the 10% weight loss temperatures ranged from 507 to 541°C in nitrogen. Meanwhile, all the PIs left around 50% residual even at 800°C in nitrogen. The GPC results indicated that the PIs possessed moderate‐to‐high number‐average molecular weight (M_n), ranging from 9609 to 17,628. Moreover, the polymer films exhibited good mechanical properties, with elongations at break of 8–21%, tensile strength of 66.5–89.8 MPa, and Young's modulus of 1.04–1.27 GPa, and low moisture uptakes of 0.54–1.13%. These excellent combination properties ensure that the polymer could be considered as potential candidates for photoelectric and microelectronic applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Organosoluble and light‐colored fluorinated polyimides based on 1,1‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]‐1‐phenylethane and various aromatic dianhydrides

To investigate the CF₃ group affecting the coloration and solubility of polyimides (PI), a novel fluorinated diamine 1,1‐bis[4‐(4‐amino‐2‐ trifluoromethylphenoxy)phenyl]‐1‐phenylethane (2) was prepared from 1,1‐ bis(4‐hydrophenyl)‐1‐phenylethan and 2‐chloro‐5‐nitrobenzotrifluoride. A series of light‐colored and soluble PI 5 were synthesized from 2 and various aromatic dianhydrides 3a–f using a standard two‐stage process with thermal 5a– f(H) and chemical 5a–f(C) imidization of poly(amic acid). The 5 series had inherent viscosities ranging from 0.55 to 0.98 dL/g. Most of 5a–f(H) were soluble in amide‐type solvents, such as N‐methyl‐2‐pyrrolidone (NMP), N,N‐ dimethylacetamide (DMAc), and N,N‐dimethylformamide (DMF), and even soluble in less polar solvents, such as m‐Cresol, Py, Dioxane, THF, and CH₂Cl₂, and the 5(C) series was soluble in all solvents. The GPC data of the 5a–f(C) indicated that the Mn and Mw values were in the range of 5.5–8.7 × 10⁴ and 8.5–10.6 × 10⁴, respectively, and the polydispersity index (PDI) Mw /Mn values were 1.2–1.5. The PI 5 series had excellent mechanical properties. The glass transition temperatures of the 5 series were in the range of 232–276°C, and the 10% weight loss temperatures were at 505–548 °C in nitrogen and 508–532 °C in air, respectively. They left more than 56% char yield at 800°C in nitrogen. These films had cutoff wavelengths between 356.5–411.5 nm, the b* values ranged from 5.0–71.1, the dielectric constants, were 3.11–3.43 (1MHz) and the moisture absorptions were in the range of 011–0.40%. Comparing 5 containing the analogous PI 6 series based on 1,1‐bis[4‐(4‐aminophenoxy)phenyl]‐1‐ phenylethane (BAPPE), the 5 series with the CF₃ group showed lower color intensity, dielectric constants, and better solubility. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2399–2412, 2005