Dynamic light-scattering characterization of the molecular weight distribution of a broadly distributed phenolphthalein poly(aryl ether ketone)

Using a recently developed laser light-scattering (LLS) procedure, we accomplished the characterization of a broadly distributed unfractionated phenolphthalein poly(aryl ether ketone) (PEK-C) in CHCl₃ at 25°C. The laplace inversion of precisely measured intensityintensity time correlation function from dynamic LLS leads us first to an estimate of the characteristic line-width distribution G(T) and then to the translational diffusion coefficient distribution G(D). By using a previously established calibration of D (cm²/s) = 2.37 ×10⁻⁴M^−0.57, we were able to convert G(D) into a differential weight distribution f_w(M). The weight-average molecular weight M_w calculated from f_w(M) agrees well with that directly measured in static LLS. Our results indicate that both the calibration and LLS procedure used in this study are ready to be applied as a routine method for the characterization of the molecular weight distribution of PEK-C. © 1996 John Wiley & Sons, Inc.     

Characterization of novel thermoplastic polymers with phenolphthalein in their backbone chains

Different molecular weight phenolphthalein poly(ether ketone) (PEK-C) and phenolphthalein poly(ether sulfone) (PES-C) fractions in chloroform (CHCl₃) were studied by static and dynamic laser light scattering (LLS). The dynamic LLS revealed that both the PEK-C and PES-C samples contain some large polymer clusters formed in the process of polymerization. These large clusters can be removed by filtering the solution with a 0.1-μm filter. The positive second virial coefficient (A₂) shows that CHCl₃ is a good solvent for these polymers at room temperature. The persistence length and the Flory characteristic ratio of these polymers in CHCl₃ at 25°C are ～2 nm and ～3, respectively, which indicate that these polymer chains are flexible. A combination of static and dynamic LLS results, namely the weight-average molecular weight from static LLS and the line-width distribution from dynamic LLS, lead to two calibrations between the translational diffusion coefficient (D) and molecular weight (M): D = 2.20 × 10^?4 M^?0.56 for PEK-C and D = 2.45 × 10^?4 M^?0.55 for PES-C in CHCl₃. Using these calibrations, we are able to estimate not only the molecular weight distributions of these fractionated polymers, but also unfractionated PEK-C and PES-C samples.     

Light-scattering and size-exclusion chromatographic characterization of hydroxyethyl cellulose acetate

A recently developed analytical method of combining off-line laser light scattering (LLS) and size exclusion chromatography (SEC) was used to investigate a set of moderately distributed hydroxyethyl cellulose acetate (HECA) samples in tetrahydrofuran (THF) at room temperature. Our results have shown that this new LLS + SEC method is suitable for the characterization of molecular weight distribution of HECA. By using this method, we have simultaneously determined two calibrations of V (cm³) = 45.3 ? 1.89 log (M) and D (cm²/s) = 2.45 × 10^?4 M^?0.60, where M is the molecular weight of HECA; V, the elution volume in SEC; and D, the translational diffusion coefficient in dynamic LLS. In addition, our results have also indicated that the chain conformation of HECA in THF at room temperature is a slightly extended linear coil. © 1995 John Wiley & Sons, Inc.     

Stereocomplex formation between poly(L‐lactic acid) and poly(D‐lactic acid) with disproportionately low and high molecular weights from the melt

Poly(L ‐lactic acid) (PLLA) and poly(D ‐lactic acid) (PDLA) with very different weight‐average molecular weights (M_w) of 4.0 × 10³ and 7.0 × 10⁵ g mol^?1 (M_w(PDLA)/M_w(PLLA) = 175) were blended at different PDLA weight ratios (X_D = PDLA weight/blend weight) and their crystallization from the melt was investigated. The presence of low molecular weight PLLA facilitated the stereocomplexation and thereby lowered the cold crystallization temperature (T_cc) for non‐isothermal crystallization during heating and elevated the radial growth rate of spherulites (G) for isothermal crystallization, irrespective of X_D. The orientation of lamellae in the spherulites was higher for the neat PLLA, PDLA and an equimolar blend than for the non‐equimolar blends. It was found that the orientation of lamellae in the blends was maintained by the stereocomplex (SC) crystallites. Although the G values are expected to decrease with an increase in X_D or the content of high‐molecular‐weight PDLA with lower chain mobility compared with that of low‐molecular‐weight PLLA, G was highest at X_D = 0.5 where the maximum amount of SC crystallites was formed and the G values were very similar for X_D = 0.4 and X_D = 0.6 with the same enantiomeric excess. This means that the effect of SC crystallites overwhelmed that of chain mobility. The nucleating mechanisms of SC crystallites were identical for X_D = 0.1–0.5 in the T_c range 130–180 °C. Copyright © 2011 Society of Chemical Industry     

Laser light-scattering study of polyacrylamides with and without hydrolyzation in 0.35M KH2PO4 aqueous solution

Both the hydrolyzed and unhydrolyzed polyacrylamides with different molar masses were characterized in 0.35M KH₂PO₄ aqueous solution at 25°C by laser light scattering (LLS). The Laplace inversion of precisely measured intensity-intensity time correlation function leads to an estimate of the characteristic line-width distribution G(Γ) which can be further reduced to a translational diffusion coefficient distribution G(D). A combination of the measured weight-average molar mass M_w and G(D) enables us to establish a calibration of D (cm²/s) = (4.46 ± 0.02) × 10⁻⁵M^{−0.50±0.003}. Using this calibration, we convert each G(D) into a corresponding molar mass distribution. The calculated M_w from such a molar mass distribution is reasonably close to the measured M_w from static LLS. Most important is that when 0.35M KH₂PO₄ aqueous solution is used as solvent, both the hydrolysed and unhydrolysed polyacrylamides can be represented by an identical calibration; namely, in 0.35M KH₂PO₄ aqueous solution, the polyelectrolytes effect in the hydrolysed polyacrylamides has been suppressed. Therefore, the hydrolysed polyacrylamides can be characterized as a normal neutral polymer in 0.35M KH₂PO₄ aqueous solution, which makes a routine characterization of the hydrolysed polyacrylamides much easier. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1755–1760, 1997     

High-temperature dynamic laser light-scattering characterization of polyethylene in trichlorobenzene

Polyethylene samples were characterized in trichlorobenzene at 135°C by high-temperature dynamic laser light scattering (LLS). Precise measurements of the intensity-intensity time correlation function permit us to make a Laplace inversion to obtain an estimate of the normalized translational diffusion coefficient distribution [G(D)]. After establishing a calibration between the translational diffusion coefficient (D) and molar mass, by using six moderately dispersed polyethylene samples, we were able to transform G(D) to molecular weight distribution (MWD), and to calculate the weight average molecular weight (M_w), which weights were comparable with the ones obtained by using static LLS and size exclusion chromatograph (SEC). The advantages and limitations of using dynamic LLS as a routine method to characterize of polyethylene are discussed. © 1993 John Wiley & Sons, Inc.     

Laser light-scattering studies of soluble high performance fluorine-containing polyimides

Two sets of soluble high performance polyimides synthesized from 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,2′-(trifluoromethyl)-4,4′-diaminobiphenyl diamine (PFMB), and from 2,2′-bis(trifluoromethyl)-4,4′,5,5′-biphenyl-tetracarboxylic dianhydride (HFBPDA) and 2,2′-(trifluoromethyl)-4,4′-diaminobiphenyl diamine (PFMB) have been investigated by static and dynamic laser light scattering (LLS) in tetrahydrofuran (THF) at 30°C. The calibrations, for 6FDA-PFMB: <R_g> (nm) = 3.87 × 10^?2 <M_w> ^0.568, <R_h> (nm) = 2.38 × 10^?2 <M_w>^0.560 and <D> (cm²/s) = 2.13 × 10^?4 <M_w>^?0.560; for HFBPDA-PFMB: <R_g> (nm) = 2.24 × 10^?2 <M_w>^0.626, <R_h> (nm) = 1.27 × 10^?2 <M_w>^0.621 and <D> (cm²/s) = 3.99 × 10^?4 <M_w>^?0.621, have been established, where <M₂>, <R_g>, <R_h> and <D> are the weight-average molar mass, the root mean square z-average radius of gyration, the z-average hydrodynamic radius and the z-average translational diffusion coefficient, respectively. A combination of <M_w> and the translational diffusion coefficient distribution G(D) leads to the calibrations of D (cm²/s) = 2.41 × 10^?4M^?0.564 and D (cm²/s) = 6.16 × 10^?4M^?0.656 for 6FDA-PFMB and HFBPDA-PFMB, respectively, where D and M correspond to monodisperse species. With these calibrations, we can convert a translational diffusion coefficient distribution G(D) into a corresponding molar mass distribution f_w(M). On the basis of the Kratky-Porod wormlike chain model, the persistence lengths (q) were found to be ? 3.3 nm and ? 4.5 nm, respectively, for 6FDA-PFMB and HFBPDA-PFMB, which indicates that both polyimide chains have an extended conformation. In addition, <R_g> / <R_h> ? (1.7-1.9) shows that they are in coil conformation. Therefore, we conclude that both polyimides have an extended coil conformation.     

Light‐scattering study of poly(hydroxy ester ether) in N,N‐dimethylacetamide solution

Static and dynamic light‐scattering techniques were used to study biodegradable thermoplastic poly(hydroxy ester ether) in N,N‐dimethylacetamide (DMAc). A weight‐average molecular weight M_W = 6.4 × 10⁴ g/mol, radius of gyration R_G = 9.4 nm, second‐virial coefficient A₂ = 1.05 × 10^?3 mol mL/g², translational diffusion coefficient D = 1.34 × 10^?7 cm²/s, and hydrodynamic radius R_H = 8.3 nm are reported. In addition, the effect of H₂O on the polymer chain's conformation and architecture in a DMAc/H₂O solution is evaluated. Results suggest that H₂O makes the mixed solvent poorer as well as promotes polymer chain branching via intramolecular transesterification. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1737–1745, 2001     

An activated neodymium‐based catalyst for styrene polymerization

Coordination polymerization of styrene with a ternary catalyst system composed of catalyst neodymium tricarboxylate (Nd), co‐catalyst Al(i‐Bu)₃ (Al) and chlorinating agent trichloroethane (Cl) was carried out in cyclohexane. The effects of the catalyst system preparation procedure and of the reaction conditions on catalytic activity, molecular weight and molecular weight distribution of the resultant polymers were investigated. The catalytic activity depended mainly on the molar ratios of Al/Nd and of Cl/Nd and on the ageing temperature and polymerization temperature. High polymerization conversion and high catalytic activity could be obtained at high Al/Nd ratios and/or at high ageing temperature. The catalyst system exhibited high activity of 8.32 × 10⁴ g polystyrene (mol Nd h)^?1 at 50 °C. The molecular weight of the polymers obtained reached high weight‐average (M_w) values (M_w = 4.35 × 10⁵ g mol^?1) when Al/Nd = 8, but relatively low values (6000–11 000 g mol^?1) at high Al/Nd ratios. Copyright © 2005 Society of Chemical Industry     

Rheological properties of concentrated solutions of agarose in ionic liquid

The rheological properties of agarose solutions were examined under the effect of entanglement coupling between agarose chains. Agarose solutions were prepared by using an ionic liquid 1‐butyl‐3‐methylimidazolium chloride as a solvent. The concentration of agarose was varied from 1.1 × 10¹–2.1 × 10² kg m^?3. The master curves of the angular frequency (ω) dependence of the storage modulus (G′) and the loss modulus (G″) showed a rubbery region in the middle ω region and a flow region at low ω region, respectively. The molecular weight between entanglements (M_e) for agarose was calculated from the plateau modulus. Moreover, M_e for agarose melt was determined to be 2.3 × 10³ from the concentration dependence curve of M_e. By using well‐known empirical relations in polymer rheology, information on molecular characteristics of sample agarose was derived. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

EDTA and pH‐sensitive crosslinking polymerization of acrylic acid, 2‐acrylamidoglycolic acid,and 2‐acrylamide‐2‐methyl‐1‐propanesulfonic acid

Network formation was monitored by shear storage modulus (G′) during free radical crosslinking polymerization to investigate the effects of pH and ethylenediaminetetraacetic acid (EDTA; a complex agent). Three types of acrylic monomers, acrylic acid (AAc), 2‐acrylamidoglycolic acid (AmGc), and 2‐acrylamido‐2‐methyl propanesulfonic acid (AmPS), were polymerized in the presence of a crosslinking agent. The ratio of crosslinking agent (methylene bis‐acrylamide; MBAAm) to monomer was varied as: 0.583 × 10^?3, 1.169 × 10^?3, 1.753 × 10^?3, and 2.338 × 10^?3. G′ of the hydrogel in crosslinking polymerizations of AAc and AmPS was effectively increased by addition of EDTA, which was not the case for the crosslinking polymerization of AmGc. The order of magnitude of G′ differed based on the acidity of monomer. The maximum values of G′ in crosslinking polymerizations of AAc, AmGc, and AmPS were ～20,000 Pa, 6000 Pa, and 400 Pa, respectively. G′ varied linearly with the molecular weight between crosslinks (M_wc). pH and EDTA‐complex affected the rate of intramolecular propagation during crosslinking polymerization. Our results indicated that G′ was primarily affected by the following factors in the order: (1) acidity of monomer, (2) M_wc, and (3) physical interactions induced by pH and EDTA. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41026.     

Molecular weight distribution of a segmented copolymer of PET–PCL

A recently developed method of combining both the results of static and dynamic laser light scattering (LLS) was applied to characterize the segmented copolymer of poly(ethylene terephthalate-co-caprolactone) (PET–PCL) with 48% PET content. Unlike the traditional three-solvent method proposed by Bushuk and Benoit for copolymers, this method requires only two solvents. For each solvent, the apparent weight average molecular weight (M_w,app) was measured by static LLS. Then M_w,app was used as a constraint to convert the line-width distribution from dynamic LLS into the apparent molecular weight distribution. Finally, the two apparent molecular weight distributions were combined to give both the true molecular weight distribution and the estimated chain composition distribution of the copolymer. We found that the PET–PCL sample with 48% PET is nearly uniform in the chain composition. © 1995 John Wiley & Sons, Inc.     

Electrochemical behavior of multifunctional graphene–polyimide nanocomposite film in two different electrolyte solutions

The effect of solvent on specific capacitance, bulk resistance, and charge/discharge capacity of graphene/polyimide composite films is studied by electrochemical methods. Composite films are synthesized by in situ condensation polymerization of poly (amic acid) in the presence of 50 wt % partly exfoliated graphene sheets followed by thermal curing at 250°C. Raman spectrum of the exfoliated graphene sheets show an increase in the ratio of I_D to I_G peak intensities from 0.167 to 0.222, suggesting increased defects in graphene basal planes. Electrochemical measurements carried out by using 0.4M potassium hexafluorophosphate (KPF₆) dissolved in propylene carbonate and N‐methylpyrrolidone at 25°C show that the composite system exhibits both pseudocapacitance and supercapacitance behaviors, with an average capacitance of 40 and 36.5 F g^?1, respectively. Bulk resistance of the composite obtained by using KPF₆–propylene carbonate electrolyte solution is 300% lower than that obtained in KPF₆–N‐methylpyrrolidone solution, with a fairly stable specific capacity of 85 μAhr g^?1, with 80% retention observed after 30 charge–discharge cycles. Fourier transform infrared spectroscopy measurements show shifts in the cyclic imide carbonyl peak from 1778 to 1774 cm^?1, which suggests that some form of interaction exists between the graphene and polyimide. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42673.     

Dynamic adsorption behaviors between Cu2+ ion and water‐insoluble amphoteric starch in aqueous solutions

Dynamic adsorption behavior between Cu²⁺ ion and water‐insoluble amphoteric starch was investigated. The sorption process occurs in two stages: external mass transport occurs in the early stage and intraparticle diffusion occurs in the long‐term stage. The diffusion rate of Cu²⁺ ion in both stages is concentration dependent. In the external mass‐transport process, the diffusion coefficient (D₁) increases with increasing initial concentration in the low‐ (1 × 10^?3‐4 × 10^?3M) and high‐concentration regions (6 × 10^?3‐10 × 10^?3M). The values of adsorption activation energy (k_d1) in the low‐ and high‐concentration regions are 15.46–24.67 and ?1.80 to ?11.57 kJ/mol, respectively. In the intraparticle diffusion process, the diffusion coefficient (D₂) increases with increasing initial concentration in the low‐concentration region (1 × 10^?3‐2 × 10^?3M) and decreases with increasing initial concentration in the high‐concentration region (4 × 10^?3‐10 × 10^?3M). The k_d2 values in the low‐ and high‐concentration regions are 9.96–15.30 and ?15.53 to ?10.71 kJ/mol, respectively. These results indicate that the diffusion process is endothermic in the low‐concentration region and is exothermic in the high‐concentration region for both stages. The external mass‐transport process is more concentration dependent than the intraparticle diffusion process in the high‐concentration region, and the dependence of concentration for both processes is about equal in the low‐concentration region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2849–2855, 2001     

The preparation of ultra narrow molecular weight distribution poly(ethylene glycol)s by fractional crystallization from solution

The preparation of very narrow molecular weight distribution poly(ethylene glycol) (PEG) was investigated by fractional crystallization from solution. Fractionation experiments were conducted from the solutions of 1500, 2000, and 3000 molecular weight PEG in n‐butanol/n‐heptane mixtures. Size Exclusion Chromatography and Differential Scanning Calorimetric studies were performed for the characterization of fractions prepared at different crystallization temperatures and times. By suitable choice of these experimental parameters it was possible to obtain PEG fractions with M_w/M_n ≤ 1.05. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1999–2005, 2001     

Melt rheological behavior of a triblock copolymer based on aramide end‐segments

Melt rheological behavior of a ABA triblock polymer made of poly(tetramethylene oxide) (PTMO) (M_n = 2,900 g mol^?1) soft segment and aramide hard segment was studied. The aramide end‐segments ( A ) were short and mono‐disperse in length. The mid‐segment ( B ) consisted of PTMO₂₉₀₀ extended with terephthalate units to a molecular weight of 9000 g mol^?1. The molecular weight of the triblock was 9700 g mol^?1. Rheological behavior of this material was studied by parallel‐plate and capillary method. The ABA triblock copolymer was compared with a B polymer (PTMO‐terephthalate) of a similar molecular weight. The low molecular weight B polymer had a Newtonian behavior. The low molecular weight triblock copolymer had at high frequencies a low complex viscosity. However, at low frequencies the triblock copolymer had a very high complex viscosity. Also the G″/G′ ratio decreased with decreasing frequency to values less then one and the G′ seemed to have at low frequencies a plateau value. The activation energy of the process increased in value with decreasing shear rate. All these results indicate that the triblock copolymer at low frequencies had a gel‐like behavior and this probably due to the clustering of the aramide segments. The aramide clusters are thought to be the (weak) network points of the gel. This network was also found to have a time dependant rheological response and thus a thixotropic behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Number‐average molecular weight of branched polymers from SEC with viscosity detection and universal calibration

BACKGROUND: Number‐average molecular weight, M?_n, is an important characteristic of synthetic polymers. One of the very few promising methods for its determination is size‐exclusion chromatography (SEC) using on‐line viscometric detection and assuming the validity of the universal calibration concept. RESULTS: We have examined the applicability of this approach to the characterization of statistically branched polymers using 22 copolymers of styrene and divinylbenzene as well as 3 homopolymers of divinylbenzene with various degrees of branching. SEC with three on‐line detectors, i.e. concentration, light scattering and viscosity, enables us to evaluate experimental data by various computational procedures yielding M?_n and weight‐average molecular weight, M?_w. Analysis of the results has shown that the universal calibration theorem has limited validity, apparently due to the dependence of the Flory viscosity function on the molecular shape, the molecular weight distribution and the expansion of molecules. CONCLUSION: For complex polymers, the universal calibration, i.e. the dependence of the product of intrinsic viscosity and molecular weight, [η]M, on elution volume, can differ in values of [η]M from those obtained for narrow molecular weight standards by 10–15%. The method studied is helpful for the determination of M?_n of polymers, in particular of those with very broad molecular weight distribution, such as statistically highly branched polymers. Copyright © 2008 Society of Chemical Industry     

Synthesis,characterization, conductivity,band gap,and kinetic of thermal degradation of poly‐4‐[(2‐mercaptophenyl) imino methyl] phenol

The oxidative polycondensation reaction conditions of 4‐[(2‐mercaptophenyl) imino methyl] phenol (2‐MPIMP) were studied in an aqueous acidic medium between 40 and 90°C by using oxidants such as air, H₂O₂, and NaOCl. The structures of the synthesized monomer and polymer were confirmed by FTIR, ¹H NMR, ¹³C NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(2‐mercaptophenyl) imino methyl]phenol (P‐2‐MPIMP) was found to be 92% for NaOCl oxidant, 84% for H₂O₂ oxidant 54% for air oxidant. According to the SEC analysis, the number‐average molecular weight (M_n), weight‐average molecular weight (M_w), and polydispersity index values of P‐2‐MPIMP were found to be 1700 g mol^?1, 1900 g mol^?1, and 1.118, using H₂O₂; 3100 g mol^?1, 3400 g mol^?1, and 1.097, using air; and 6750 g mol^?1, 6900 g mol^?1, and 1.022, using NaOCl, respectively. According to TG analysis, the weight losses of 2‐MPIMP and P‐2‐MPIMP were found to be 95.93% and 76.41% at 1000°C, respectively. P‐2‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐2‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, and the electrochemical energy gaps (E′_g) of 2‐MPIMP and P‐2‐MPIMP were found to be ?6.13, ?6.09; ?2.65, ?2.67; and 3.48, 3.42 eV, respectively. Kinetic and thermodynamic parameters of these compounds investigated by MacCallum‐Tanner and van Krevelen methods. The values of the apparent activation energies of thermal decomposition (E_a), the reaction order (n), pre‐exponential factor (A), the entropy change (ΔS*), enthalpy change (ΔH*), and free energy change (ΔG*) were calculated from the TGA curves of compounds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The synthesis of high molecular weight polybutene‐1 catalyzed by Cp★ Ti(OBz)3/MAO

A new stereoregular polybutene‐1 was synthesized with a novel catalyst precursor η⁵‐pentamethyl cyclopentadienyl titanium tribenzyloxide (CpTi(OBz)₃) and methylaluminoxane (MAO). The effects of polymerization conditions on the catalytic activity, molecular weight and stereoregularity of the products were investigated in detail. It was found the catalyst exhibited highest activity of 91.2 kgPB mol Ti⁻¹ h⁻¹ at T = 30 °C, Al/Ti = 200. The catalytic activity and molecular weight were sensitive to the Al/Ti (mole/mole), polymerization temperature; they also depended on the Ti concentration. The molecular weight of the products increased with decreasing temperature. The structure and properties of the polybutene‐1 were characterized by ¹³C NMR, GPC, DSC and WAXD. The result showed the microstructure of polybutene‐1 extracted by boiling heptane was stereoregular, whereas the ether‐soluble fraction was atactic. The molecular weight of polybutene‐1 was over one million g mol⁻¹ and its molecular weight distribution ( M _w/ M _n) was from 1.1 to 1.2. © 2001 Society of Chemical Industry     

Anionic polymerization of secondary aminostyrene and characterization of the polymer

Preparation by anionic living technique and characterization of poly(secondary aminostyrene) having narrow molecular weight distribution were investigated. N‐isopropyl‐N‐trimethylsilyl‐4‐vinylbenzylamine (SBA) was purified by use of sec‐butylmagnesium bromide as a purging reagent under high vacuum. SBA was anionically polymerized with n‐butyllithium or cumylpotassium in tetrahydrofuran at −78°C under high vacuum to yield the corresponding polymer (PSBA) in 100% yield. Subsequent deprotection of the trimethylsilyl group from PSBA produced poly(N‐isopropyl‐4‐vinylbenzylamine) (PBA) of the desired molecular weights (M_n: 1.3 × 10⁴–17 × 10⁴, determined by membrane osmometry) with narrow molecular weight distribution (M_w/M_n: 1.07–1.03, determined by gel permeation chromatography). The living lithium carbanion of PSBA can initiate styrene (St) to yield PSBA‐b‐PSt block copolymer (M_n = 4.0 × 10⁴, M_w/M_n = 1.05), and the polystyryllithium can initiate SBA to yield PSt‐b‐PSBA (M_n = 3.7 × 10⁴, M_w/M_n = 1.25). The deprotection of the trimethylsilyl group from the two block copolymers produced new block copolymers containing poly(secondary aminostyrene) block. Anionic reactivity of SBA and basic properties of PSBA are discussed in terms of the ¹³C chemical shift of β‐carbon in the vinyl group of SBA and steric effect. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2039–2048, 1999