Characterization of optical properties of acrylate based adhesives exposed to different temperature conditions

Optical adhesives combine the traditional function of structural attachment with a more advanced function of providing an optical path between optical interconnects. This article aims to characterize refractive index and birefringence of such adhesives under environmental exposure to different temperature conditions. Optical time domain reflectometery (OTDR) and prism coupling methods were employed to measure optical properties of an optical adhesive. Thermo‐optic coefficient (dn/dT) of the adhesive was observed to decrease noticeably from ?2 × 10^?4°C^?1 to ?4 × 10^?4°C^?1 around the glass transition temperature (T_g ～ 78°C). It is observed that refractive indices for both T_E and T_M modes increase with increasing annealing temperature, but the birefringence (T_E ? T_M) is decreasing. This suggests that the material has become more isotropic due to the annealing. The environmental changes in optical properties of the adhesive are discussed in the light of Lorentz–Lorenz equations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 950–956, 2005     

Simple dilatometer for polymer density and thermal expansivity measurements

A dilatometer is described to study the temperature dependence of density (ρ) of solid and semiliquid polymers and the following linear relations have been established. Atactic poly(vinylisobutyl ether) (25–90°C): ρ = 0.9166 ? 7.15 × 10^?4 × T. Isotactic poly(vinylisobutyl ether) (25–70°C): ρ = 0.9184 ? 7.13 × 10^?4 × T. Poly(n-butyl methacrylate) (90–150°C): ρ = 1.0622 ? 8.41 × 10^?4 × T. Poly(dimethyl siloxane) (30–51°C, using Lipkins pycnometer): ρ = 0.9846 ? 8.81 × 10^?4 × T; where ρ is in g.cm^?3, temperature T is in Celsius, and the linearity correlation coefficient r is better than 0.9998. Their volume–temperature plots are also linear. As the plots of polyn-butyl methacrylate curved slightly near its glass transition (20°C), the quadratic equation ρ = 1.0402 ? 4.79 × 10^?4 × T ? 1.46 × 10^?6 × T² (standard deviation = 1.57 × 10^?3) has been suggested for the entire range of 30–150°C scrutinized in this study. The data have been utilized to derive thermal expansivity and some equation-of-state parameters of the polymers at the reference temperature (ca. 20°C).     

Effect of temperature on viscosity of amylose

Viscosity parameters were obtained for maize maylose (molecular weight of 107,000) in 1N KOH at 25, 30, 35, and 40°C. Intrinsic viscosity continuously decreased and Huggins' constant k' continuously increased with increasing temperature. The temperature dependence of intrinsic viscosity, d[η]/dT, was ?2.12 × 10^?2/°C.     

Ceric ion‐induced graft copolymerization of acrylamide on cationic guar gum at low temperature

The solution polymerization of acrylamide (AM) on cationic guar gum (CGG) under nitrogen atmosphere using ceric ammonium sulfate (CAS) as the initiator has been realized. The effects of monomer concentration and reaction temperature on grafting conversion, grafting ratio, and grafting efficiency (GE) have been studied. The optimal conditions such as 1.3 mol of AM monomer and 2.2 × 10^?4 mol of CAS have been adopted to produce grafted copolymer (CGG1‐g‐PAM) of high GE of more than 95% at 10°C. The rates of polymerization (R_p) and rates of graft copolymerization (R_g) are enhanced with increase in temperature (<35°C).The R_p is enhanced from 0.43 × 10^?4 mol L^?1 s^?1 for GG‐g‐PAM to 2.53 × 10^?4 mol L^?1 s^?1 for CGG1‐g‐PAM (CGG1, degree of substitute (DS) = 0.007), and R_g from 0.42 × 10^?4 to 2.00 × 10^?4 mol L^?1 s^?1 at 10°C. The apparent activation energy is decreased from 32.27 kJ mol^?1 for GG‐g‐PAM to 8.09 kJ mol^?1 for CGG1‐g‐PAM, which indicates CGG has higher reactivity than unmodified GG ranging from 10 to 50°C. Increase of DS of CGG will lead to slow improvement of the polymerization rates and a hypothetical mechanism is put forward. The grafted copolymer has been characterized by infrared spectroscopy, thermal analysis, and scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3715–3722, 2007     

The preparation,characterization, and cure reactions of new bisbenzocyclobutene‐terminated aromatic imides

Several new bisbenzocyclobutene‐terminated aromatic imides, 2,2′‐bis(N‐4‐benzocyclobutenyl) phthalimide, 2,2′‐bis[4‐(N‐4‐benzocyclobutenylphthalimide)]‐ether, 2,2′‐bis[4‐(N‐4‐benzocyclobutenylphthalimide)]‐ketone, and 2,2′‐bis[4‐(N‐4‐benzo cyclobutenylphthalimid‐4‐oxy) phenyl]‐propane, have been synthesized in high yields and characterized by FTIR, MS, EA, and ¹H NMR spectroscopy. The polymers cured from benzocyclobutene‐terminated imides have high glass transition temperature and good thermal stabilities. The cure reaction of an imide was studied by FTIR‐ATR (attenuated total reflection) and DSC techniques. Apparent kinetic parameters of the cure reaction are obtained. The apparent cure reaction order, activation energy, and pre‐exponential factor determined by isothermal DSC method are 1, 143.4 kJ/mol, and 3.88× 10¹³ min^?1, and by nonisothermal DSC methods 1, 139.4 kJ/mol, and 2.27× 10¹³ min^?1, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1705–1719, 2006     

Thiophene‐ and silarylene‐containing polyesters. Resonance effect on conductivity after polarization in an external electric field

Polyesters were synthesized by direct polycondensation of thiophene‐2,5‐dicarboxylic acid and five different silarylene‐containing diphenols using a tosyl chloride/pyridine/N,N‐dimethylformamide system as a condensing agent. Polymers were obtained in good yields and were characterized using Fourier transform infrared and NMR (¹H, ¹³C, 135‐DEPT and ²⁹Si) spectroscopy and elemental analysis. All polymers were completely soluble in aprotic organic polar solvents such as dimethylformamide, dimethylsulfoxide and N‐methyl‐2‐pyrrolidone. The range of effective mass of the polymers (m/z) was 1 × 10⁵–2 × 10⁵, determined using electrospray ionization mass spectrometry. Asymmetry and steric hindrance prevented dense packing of the polymeric chains, showing glass transition temperatures between ? 78 and ? 51 °C and loss of thermal stability at 177–199 °C (10% weight loss). Additionally, the melting points of the polyesters were found to be in the range 62–67 °C. Because of this, the samples were semi‐solid at room temperature. The optical band gaps of the polymers were observed between 4.54 and 4.48 eV, corresponding in all cases to insulator behavior. The molecular structure of the samples was studied using X‐ray diffraction, showing a degree of order that was associated with two monoclinic lattices. Additionally, the conductivity was studied using a two‐point method with contacts on top of polymer films. Prior to the electrical measurement, the samples were polarized in an external electric field of 0.8 to 6.4 V cm^?1, and the alignment of the dipoles increased the electrical conductivity. Copyright © 2012 Society of Chemical Industry     

The β‐δ‐Phase Transition and Thermal Expansion of Octahydro‐1,3,5,7‐Tetranitro‐1,3,5,7‐Tetrazocine

Phase behavior of octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) is investigated by X‐ray powder diffraction (XRD). The XRD patterns at elevated temperature show that there is a co‐existing temperature range of β‐ and δ‐phase during the phase transition process. Additionally, mechanical forces can catalyze the conversion from δ‐ back to β‐phase. Based on the diffraction patterns of β‐ and δ‐phase at different temperatures, we calculate the coefficients of thermal expansion by Rietveld refinement. For β‐HMX, the linear coefficients of thermal expansion of a‐axis and b‐axis are about 1.37×10⁻⁵ and 1.25×10⁻⁴ °C⁻¹. A slight decrease in c‐axis with temperature is also observed, and the value is about −0.63×10⁻⁵ °C⁻¹. The volume coefficient of thermal expansion is about 1.60×10⁻⁴ °C⁻¹, with a 2.2% change from 30 to 170 °C. For δ‐HMX, the linear coefficients of thermal expansion of a‐axis and c‐axis are found to be 5.39×10⁻⁵ and 2.38×10⁻⁵ °C⁻¹, respectively. The volume coefficient of thermal expansion is about 1.33×10⁻⁴ °C⁻¹, with a 2.6% change from 30 to 230 °C. The results indicate that β‐HMX has a similar volume coefficient of thermal expansion compared with δ‐HMX, and there is about 10.5% expansion from β‐HMX at 30 °C to δ‐HMX at 230 °C, of which about 7% may be attributed to the reconstructive transition.     

Effect of pressure and temperature on viscosity of a borosilicate glass

During industrial glass production processes, the actual distribution of stress components in the glass during scribing remains, to date, poorly quantified, and thus continues to be challenging to model numerically. In this work, we experimentally quantified the effect of pressure and temperature on the viscosity of SCHOTT N‐BK7^® glass, by performing in situ deformation experiments at temperatures between 550 and 595°C and confining pressures between 100 and 300 MPa. Experiments were performed at constant displacement rates to produce almost constant strain rates between 9.70 × 10^?6 and 4.98 × 10^?5 s^?1. The resulting net axial stresses range from 81 to 802 MPa, and the finite strains range from 1.4% to 8.9%. The mechanical results show that the SCHOTT N‐BK7^® glass is viscoelastic near the glass transition temperature at 300 MPa of confining pressure. To elucidate the data, we incorporated both 1‐element and 2‐element generalized Maxwell viscoelastic models in an inversion approach, for which we provide MATLAB scrips. Results show that the 2‐element Maxwell model fits the experimental data well. The stress decreases with increasing temperature at 300 MPa and the temperature dependence yields a similar activation energy (601 ± 10 kJ mol^?1 or ?H/R = 7.2 × 10⁴ K) to a previously reported value at 1‐atm (615 kJ mol^?1 or ?H/R = 7.4 × 10⁴ K). The SCHOTT N‐BK7^® glass shows a limited linear increase in viscosity with increasing pressure of ~0.1 log₁₀ (Pa·s)/100 MPa, which is in agreement with the most recent 2‐internal‐parameter relaxation model (based on experiments).     

Preparation and characterization of sulfonated block‐graft copolyimide/sulfonated polybenzimidazole blend membranes for fuel cell application

Polymer electrolyte blend membranes composed of sulfonated block‐graft polyimide (S‐bg‐PI) and sulfonated polybenzimidazole (sPBI) were prepared and characterized. The proton conductivity and oxygen permeability coefficient of the novel blend membrane S‐bg‐PI/sPBI (7 wt%) were 0.38 S cm^?1 at 90 °C and 98% relative humidity and 7.2 × 10^?13 cm³(STP) cm (cm² s cmHg)^?1 at 35 °C and 76 cmHg, respectively, while those of Nafion^® were 0.15 S cm^?1 and 1.1 × 10^?10 cm³(STP) cm (cm² s cmHg)^?1 under the same conditions. The apparent (proton/oxygen transport) selectivity calculated from the proton conductivity and the oxygen permeability coefficient in the S‐bg‐PI/sPBI (7 wt%) membrane was 300 times larger than that determined in the Nafion membrane. Besides, the excellent gas barrier properties based on an acid ? base interaction in the blend membranes are expected to suppress the generation of hydrogen peroxide and reactive oxygen species, which will degrade fuel cells during operation. The excellent proton conductivity and gas barrier properties of the novel membranes promise their application for future fuel cell membranes. © 2015 Society of Chemical Industry     

Preparation and characterization of novel hybrid thermoplastic poly(ether urethane)/poly(vinylidene fluoride) elastomers,and their application as solid polymer electrolytes

A comb‐like polyether, poly(3‐2‐[2‐(2‐methoxyethoxy)ethoxy]ethoxymethyl‐3′‐methyloxetane) (PMEOX), was reacted with hexamethylene diisocyanate and extended with butanediol in a one‐pot procedure to give novel thermoplastic elastomeric poly(ether urethane)s (TPEUs). The corresponding hybrid solid polymer electrolytes were fabricated through doping a mixture of TPEU and poly(vinylidene fluoride) with three kinds of lithium salts, LiClO₄, LiBF₄ and lithium trifluoromethanesulfonimide (LiTFSI), and were characterized using differential scanning calorimetry, thermogravimetric analysis and Fourier transform infrared spectroscopy. The ionic conductivity of the resulting polymer electrolytes was then assessed by means of AC impedance measurements, which reached 2.1 × 10^?4 S cm^?1 at 30 °C and 1.7 × 10^?3 S cm^?1 at 80 °C when LiTFSI was added at a ratio of O:Li = 20. These values can be further increased to 3.5 × 10^?4 S cm^?1 at 30 °C and 2.2 × 10^?3 S cm^?1 at 80 °C by introducing nanosized SiO₂ particles into the polymer electrolytes. Copyright © 2006 Society of Chemical Industry     

Molecular design,synthesis, and electro‐optic properties of novel Y‐type polyesters with high thermal stability of second harmonic generation

3,4‐Di‐(2′‐hydroxyethoxy)‐4′‐nitrostilbene was prepared and condensed with terephthaloyl chloride, adipoyl chloride, and sebacoyl chloride to yield novel Y‐type polyesters containing NLO‐chromophore dioxynitrostilbenyl groups, which constituted parts of the polymer backbone. Polymers were found soluble in common organic solvents such as acetone and N,N‐dimethylformamide. They showed thermal stability up to 300 °C in thermogravimetric analysis with glass‐transition temperatures obtained from differential scanning calorimetry in the range 110–152 °C. The second harmonic generation (SHG) coefficients (d₃₃) of poled polymer films at a 1064 cm^?1 fundamental wavelength were around 3.51 × 10^?8 esu. The dipole alignment exhibited high thermal stability even at 10 °C higher than the glass‐transition temperature, and there was no SHG decay below 120 °C for one of these polymers due to the partial main‐chain character of polymer structure, which was acceptable for NLO device applications. Copyright © 2005 Society of Chemical Industry     

New organic–inorganic hybrid membranes based on sulfonated polyimide/aminopropyltriethoxysilane doping with sulfonated mesoporous silica for direct methanol fuel cells

A series of novel composite methanol‐blocking polymer electrolyte membranes based on sulfonated polyimide (SPI) and aminopropyltriethoxysilane (APTES) doping with sulfonated mesoporous silica (S‐mSiO₂) were prepared by the casting procedure. The microstructure and properties of the resulting hybrid membranes were extensively characterized. The crosslinking networks of amino silica phase together with sulfonated mesoporous silica improved the thermal stability of the hybrid membranes to a certain extent in the second decomposition temperature (250–400°C). The composite membranes doping with sulfonated mesoporous silica (SPI/APTES/S‐mSiO₂) displayed superior comprehensive performance to the SPI and SPI/APTES membranes, in which the homogeneously embedded S‐mSiO₂ provided new pathways for proton conduction, rendered more tortuous pathways as well as greater resistance for methanol crossover. The hybrid membrane with 3 wt % S‐mSiO₂ into SPI/APTES‐4 (SPI/A‐4) exhibited the methanol permeability of 4.68 × 10^?6 cm² s^?1at 25°C and proton conductivity of 0.184 S cm^?1 at 80°C and 100%RH, while SPI/A‐4 membrane had the methanol permeability of 5.16 × 10^?6 cm² s^?1 at 25°C and proton conductivity of 0.172 S cm^?1 at 80°C and 100%RH and Nafion 117 exhibited the values of 8.80 × 10^?6 cm² s^?1 and 0.176 S cm^?1 in the same test conditions, respectively. The hybrid membranes were stable up to about 80°C and demonstrated a higher ratio of proton conductivity to methanol permeability than that of Nafion117. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of a positive‐working,aqueous‐base‐developable photosensitive polyimide precursor

A positive‐working, aqueous‐base‐developable photosensitive polyimide precursor based on poly(amic ester)‐bearing phenolic hydroxyl groups and a diazonaphthoquinone photosensitive compound was developed. The poly(amic ester) was prepared from a direct polymerization of 2,2′‐bis‐(3‐amino‐4‐hydroxyphenyl)hexafluoropropane and bis(n‐butyl)ester of pyromellitic acid in the presence of phenylphosphonic dichloride as an activator. Subsequently, the thermal imidization of the poly(amic ester) precursor at 300°C produced the corresponding polyimide. The inherent viscosity of the precursor polymer was 0.23 dL/g. The cyclized polyimide showed a glass‐transition temperature at 356°C and a 5% weight loss at 474°C in nitrogen. The structures of the precursor polymer and the fully cyclized polymer were characterized by Fourier transform infrared spectroscopy and ¹H‐NMR. The photosensitive polyimide precursor containing 25 wt % diazonaphthoquinone photoactive compound showed a sensitivity of 150 mJ/cm² and a contrast of 1.65 in a 3 μm film with 1.25 wt % tetramethylammonium hydroxide developer. A pattern with a resolution of 10 μm was obtained from this composition. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 352–358, 2002     

Enhancing the electrical conductivity of vanadate glass system (Fe2O3, B2O3, V2O5) via doping with sodium or strontium cations

Novel glass-ceramics of the nominal molar compositions 20Fe₂O₃·20B₂O₃·(60-x)V₂O₅· (xNa₂O or xSrO) (where x?=?0 or 10) were prepared by traditional melt technique. Differential thermal analysis (DTA) was implemented to study the thermal behavior of the prepared glasses. Vanadium pentoxide (V₂O₅), iron vanadate (FeVO₄), sodium vanadate (Na₃VO₄) and strontium vanadate (with different formulae) were crystallized and identified by X-ray diffraction (XRD) analysis under certain conditions of heat-treatment. Further characterization of glass and glass ceramics samples were performed using scanning electron microscope (SEM), density, electrical and dielectric measurements. In conclusion, our study elucidated that the substitution of vanadium by Na⁺ and Sr²⁺ ions enhanced the conductivity at 180?°C from 5.11?×?10^?4 for unmodified glass to 2.93?×?10^?3 and 1.03?×?10^?2?S?cm^?1 for Na- and Sr-modified glasses.     

Ultra‐Low Fire Glass‐Free Li3FeMo3O12 Microwave Dielectric Ceramics

A new ultra‐low fire glass‐free microwave dielectric material Li₃FeMo₃O₁₂ was investigated for the first time. Single phase ceramics were obtained by the conventional solid‐state route after sintering at 540°C–600°C. The atomic packing fraction, FWHM of the A_g oxygen‐octahedron stretching Raman mode and Qf values of samples sintered at different temperatures correlated well with each other. The sample with a Lower Raman shift showed a higher dielectric constant. Interestingly, the system also showed a distinct adjustable temperature coefficient of resonant frequency (from ?84× 10^?6/°C to 25 × 10^?6/°C).     

Barrier and thermal properties of polyimide derived from a diamine monomer containing a rigid planar moiety

An aromatic polyimide (3,6‐CPI ) was prepared by the polymerization of pyromellitic dianhydride and diamine (3,6‐CDA ) containing a rigid planar carbazole moiety. The synthesized polyimide shows outstanding barrier properties with oxygen permeation rate and water vapor permeation rate low at 7.9 cm³ m^?2 day^?1 and 9.8 g m^?2 day^?1, respectively. Wide angle X‐ray diffraction, positron annihilation lifetime spectroscopy and molecular dynamics simulations reveal that the excellent barrier properties of 3,6‐CPI are mainly due to the crystallinity and low free volume of the polymer, which result from the rigid planar backbone structure and strong interchain hydrogen bonding. In addition, the polyimide exhibits excellent thermal stability and favorable mechanical properties with a 5 wt% weight‐loss temperature of 559 °C in nitrogen, a glass transition temperature (T _g) of 397 °C and a tensile strength of 115.4 MPa . The as‐synthesized polyimide shows potential packaging applications in the field of flexible electronics and displays, flexible and thin film photovoltaics, and light‐emitting diodes. © 2017 Society of Chemical Industry     

Ionic Liquid with Silyl Substituted Cation: Thermophysical and CO2/N2 Permeation Properties

Novel functionalized ionic liquid (IL) combining an imidazolium‐based cation with branched alkyl chain bearing silyl group, 1‐methyl‐3‐(2‐methyl‐3‐(trimethylsilyl)propyl)imidazolium ([Si?C₁?C₃‐mim]⁺), and bis(trifluoromethylsulfonyl)imide ([NTf₂]^?) anion was synthesized and its thermophysical properties (density, viscosity, surface tension, surface entropy and enthalpy, thermal stability) were studied in a wide temperature range and compared with those of ILs having linear alkyl ([C_n‐mim][NTf₂]) and siloxane ([(SiOSi)C₁mim][NTf₂]) side chains. It was found that at 25 °C [Si?C₁?C₃‐mim][NTf₂] is a liquid with dynamic viscosity of 224 cP (224 mPa s) and density of 1.32 g cm^?3. The presence of side branched alkyl chain with trimethylsilyl end‐group prevents crystallization of IL and leads to higher viscosities and lower densities in comparison with commonly known [C_n‐mim][NTf₂] (n=2–4). As surface excess enthalpy was found to be in the lower end of the usual range of values for ILs, the interactions between silyl‐functionalized cation and [NTf₂] anion can be considered as relatively weak. Finally, [Si?C₁?C₃‐mim][NTf₂] was used for the preparation of polymer supported ionic liquid membranes (SILMs) and their CO₂ and N₂ permeation properties at 20 °C and 100 kPa were determined: permeability PCO₂=311, PN₂=12 Barrer, diffusivity DCO₂=115×10¹², DN₂=227×10¹² m² s^?1 and CO₂/N₂ permselectivity αCO₂/N₂=25.3.     

Optically Active Polyurethane Containing Asymmetric Center: Preparation,Characterization and Thermo-Optic Properties

Optically active azobenzene polyurethane (OAAPU) containing donor-Π-acceptor azo group and asymmetric center was obtained from chromophore NABZ, chiral reagent L(-)-tartaric acid and toluene diisocyanate (TDI). The chemical structure and the thermal property were characterized by UV-Vis spectroscopy, FT-IR, 1H NMR and differential scanning calorimeter. The optical switching parameters: refractive indices, thermo-optic coefficients, the dielectric constants and volume expansion coefficients of OAAPU were obtained. The refractive index of OAAPU polymer decreased linearity with the increasing of temperature at the same OAAPU content and had a high thermo-optic coefficient ?4.0714–?3.8686×10^?4°C^?1. The conclusion has a little significance to develop new digital optical switch material.     

Modification of dextran through the grafting of N‐vinyl‐2‐pyrrolidone and studies of physicochemical phenomena in terms of metal‐ion uptake,swelling capacity,and flocculation

The optimum conditions for grafting N‐vinyl‐2‐pyrrolidone onto dextran initiated by a peroxydiphosphate/thiourea redox system were determined through the variation of the concentrations of N‐vinyl‐2‐pyrrolidone, hydrogen ion, potassium peroxydiphosphate, thiourea, and dextran along with the time and temperature. The grafting ratio increased as the concentration of N‐vinyl‐2‐pyrrolidone increased and reached the maximum value at 24 × 10^?2 mol/dm³. Similarly, when the concentration of hydrogen ion increased, the grafting parameters increased from 3 × 10^?3 to 5 × 10^?3 mol/dm³ and attained the maximum value at 5 × 10^?3 mol/dm³. The grafting ratio, add‐on, and efficiency increased continuously with the concentration of peroxydiphosphate increasing from 0.8 × 10^?2 to 2.4 × 10^?2 mol/dm³. When the concentration of thiourea increased from 0.4 × 10^?2 to 2.0 × 10^?2 mol/dm³, the grafting ratio attained the maximum value at 1.2 × 10^?2 mol/dm³. The grafting parameters decreased continuously as the concentration of dextran increased from 0.6 to 1.4 g/dm³. An attempt was made to study some physicochemical properties in terms of metal‐ion sorption, swelling, and flocculation. Dextran‐g‐N‐vinyl‐2‐pyrrolidone was characterized with infrared spectroscopy and thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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