共查询到20条相似文献,搜索用时 31 毫秒
1.
The method has been proposed for determining the molecular characteristics of flexible-chain polymers that obey the universal calibration principle and for which there are available experimental data on the intrinsic viscosity. This method is based on studying the dependence of the hydrodynamic volume M n[η], M w[η], M z[η], and M η[η] on parameter a in the Mark-Kuhn-Houwink equation. It has been found that, for parameter a varying in the range from 0.5 to 0.8, the weight-average hydrodynamic volume M w[η] remains almost unchanged. This allows estimation of M w based on a single intrinsic viscosity value. The notion of the chromatographic mass of a polymer is advanced and is employed for determining other molecular mass parameters. 相似文献
2.
Mitsuru Ueda Setsuo Ishibashi Toshiyuki Suzuki Toru Masuko Charles U. Pittman 《Journal of polymer science. Part A, Polymer chemistry》1984,22(10):2305-2316
The kinetics of methoxymethyl methacrylate (MOMA) homopolymerization has been investigated in benzene, using azobis(isobutyronitrile) as an initiator. The rate of polymerization (Rp) could be expressed by Rp = k[AIBN]0.5 [MOMA]1.19. The overall activation energy was calculated to be 73.2 kJ/mol. Kinetic constants for MOMA polymerization were obtained as follows: kp/kt1/2 = 0.091 L1/2 · mol?1/2 · s?1/2; 2fkd = 1.37 × 10?5 s?1. The values of K and a in the Mark–Houwink equation, [η] = KMa, where K = 5.89 × 10?5 and a = 0.82 when M = M n and the solvent was benzene. The relative reactivity ratios of MOMA (M2) copolymerizations with styrene (r1 = 0.40, r2 = 0.58) were obtained. Applying the Q-e scheme led to Q = 0.78 and e = 0.67. The glass transition temperature (Tg) of poly(MOMA) was observed to be 64°C by DSC. Thermogravimetry of poly(MOMA) showed a 10% weight loss at 230°C in air. 相似文献
3.
William W. Graessley Henry M. Mittelhauser 《Journal of Polymer Science.Polymer Physics》1967,5(3):431-454
The relationships between molecular weight distribution and structure in polymerizations with long-chain branching were reviewed and extended. Results were applied to an experimental examination of intrinsic viscosity in polydisperse, trifunctionally branched systems. Several samples of poly(vinyl acetate) were prepared by bulk polymerization under conditions of very low radical concentration. The relative rate constants for monomer transfer, polymer transfer, and terminal double-bond polymerization were established from the variation of M n and M w with the extent of conversion. Average branching densities were then calculated for each sample and ranged as high as 1.5 branch points/molecule. Intrinsic viscosities [η]B were measured in three systems: a theta-solvent, a good solvent, and one that was intermediate in solvent interaction. These results were compared with calculated viscosities, [η]L, which would have been observed if all the molecules had been linear. The values of [η]B/[η]L were substantially the same in all three solvents. The variation of this ratio with branching density was compared with the theory of Zimm and Kilb as adapted to polydisperse systems. Discrepancies were noted, and the adequacy of present model distribution functions for branched polymers was questioned. 相似文献
4.
Unperturbed dimensions of flexible linear macromolecules can be obtained from [η]-M-data in any solvent, good or poor, single or mixed. Usually Kθ is estimated by a relationship between [η]/MW0.5 and Mw0.5 first proposed by Burchard and by Stockmayer and Fixman. But, it is well-known that the Burchard-Stockmayer-Fixman-plot shows downward curvature, especially for good solvent systems. Various efforts have been made to achieve relations with better linearity. One of the first was the semi-empirical relation between ([η]/Mw0.5)0.5 and Mw/[η] by Berry. Predicting a relationship of the excluded volume parameter z to the viscosity expansion factor by α5η instead of α5η Tanaka obtains that ([η]/Mw0.5)5/3 is linear in Mw0.5. By allowing for the dependence of the viscometric interaction parameter B, which is correlated to the second virial coefficient A2, on molar mass, Gavara, Campos and Figueruelo predict a linear dependence of [η]/Mw0.5 against A2.Mw0.5. It is not our intention here to discuss the validity of these theories, but to compare them with experimental data. 相似文献
5.
By choosing suitable approximations to Bueche's function, it is possible to calculate the viscosity versus shear stress for log-normal molecularly distributed linear polymers. For bulk polymers the mixing rules M?w, M?w, M?z are considered. For values of η/η0 > 0.1 and heterogeneities with M?w/M?n > 1.5 the result obtained with any mixing rule is η/η0 = erfc [(1/delta;) log (M0Qh/aK)], where a = π2/6pRT and where the δ and K values are dependent on the heterogeneity ratio Q = M?w/M?n and on the type of mixing rule; on the other hand, the h value is independent of the heterogeneity, but depends on the mixing rule. Most experimental data should fit the M?w mixing rule as one would expect from the zero shear stress mixing rule. Experimental data are compared with the theoretical results. 相似文献
6.
《Journal of Coordination Chemistry》2012,65(4):263-270
Abstract The kinetics and stability constants of l-tyrosine complexation with copper(II), cobalt(II) and nickel(II) have been studied in aqueous solution at 25° and ionic strength 0.1 M. The reactions are of the type M(HL)(3-n)+ n-1 + HL- ? M(HL)(2-n)+n(kn, forward rate constant; k-n, reverse rate constant); where M=Cu, Co or Ni, HL? refers to the anionic form of the ligand in which the hydroxyl group is protonated, and n=1 or 2. The stability constants (Kn=kn/k-n) of the mono and bis complexes of Cu2+, Co2+ and Ni2+ with l-tyrosine, determined by potentiometric pH titration are: Cu2+, log K1=7.90 ± 0.02, log K2=7.27 ± 0.03; Co2+, log K1=4.05 ± 0.02, log K2=3.78 ± 0.04; Ni2+, log K1=5.14 ± 0.02, log K2=4.41 ± 0.01. Kinetic measurements were made using the temperature-jump relaxation technique. The rate constants are: Cu2+, k1=(1.1 ± 0.1) × 109 M ?1 sec?1, k-1=(14 ± 3) sec?1, k2=(3.1 ± 0.6) × 108 M ?1 sec?1, k?2=(16 ± 4) sec?1; Co2+, k1=(1.3 ± 0.2) × 106 M ?1 sec?1, k-1=(1.1 ± 0.2) × 102 sec?1, k2=(1.5 ± 0.2) × 106 M ?1 sec?1, k-2=(2.5 ± 0.6) × 102 sec?1; Ni2+, k1=(1.4 ± 0.2) × 104 M ?1 sec?1, k-1=(0.10 ± 0.02) sec?1, k2=(2.4 ± 0.3) × 104 M ?1 sec?1, k-2=(0.94 ± 0.17) sec?1. It is concluded that l-tyrosine substitution reactions are normal. The presence of the phenyl hydroxyl group in l-tyrosine has no primary detectable influence on the forward rate constant, while its influence on the reverse rate constant is partially attributed to substituent effects on the basicity of the amine terminus. 相似文献
7.
Anthony R. Cooper 《Journal of Polymer Science.Polymer Physics》1974,12(10):1969-1977
Gel permeation chromatographic (GPC) separations have been performed with several commercially available column packing materials. The results have been analyzed in the conventional manner to obtain the ratio of weight average to number-average molecular weight, Mw/Mn, for solutes with narrow molecular weight distribution. Various other parameters proposed to measure the efficiency of GPC columns have been evaluated and compared. It is proposed that the experimentally determined value of Mw/Mn for a series of different molecular weight samples with similar, narrow distribution for a given set of columns is a convenient parameter for comparing column efficiency in GPC. This parameter may be calculated from a single chromatogram unlike resolution, R, resolution index, RI, or specific resolution, RS, which require a pair of chromatograms. Results from the Mw/Mn method are usually in agreement with those from the R, RI, and RS calculations but one exception has been found. The number of theoretical plates calculated from the elution of a small molecule or from the polymer peak bears little relation to efficiencies predicted from the proposed Mw/Mn method or from R, RI, or RS. 相似文献
8.
Katsukiyo Ito 《Journal of polymer science. Part A, Polymer chemistry》1976,14(7):1761-1771
In the copolymerization of monomers M1 and M2 which form polymer radicals of chain length n of N1n with electron on a M1 type and N2n with one on a M2 type, it is assumed that the specific rates of termination between N1n and N1n and N1s, N1n and N2s, and N2n and N2s are kα(ns)?a, kβ(ns)?a, and kγ(ns)?a, respectively, where kα, kβ, and kγ are the rate constants of reaction between segment radicals in the respective termination, and a is constant. The relation between kinetic chain length n? and polymerization rate Rp is derived as: 1/n? = 1/n?0 + const. (Rp)A(a), where n?0 is the kinetic chain length of the polymer formed by transfer and A (a) is unity (predominance of transfer) and 1/(1–2a) (no transfer). In the copolymerization between methyl methacrylate (M1) and styrene (M2) at 60°C, when Rp → 0, kr12/k12 + kr21/k21 = 5.9× 10?5 is obtained, where kr12 and kr21 are the rate constants of transfer of N1 to M2 and N2 to M1, and k12 and k21 are the rate constants of propagation of N1 to M2 and N2 to M1. In the absence of transfer, the a value is found to be 0.065 ± 0.008, from the relation between n? and Rp, regardless of the monomer composition. Such a value is also estimated by setting b = 0.72 in a = 0.153 (2b–1), where b is the constant in the Mark-Houwink equation. Further, the value of kβ is found to be 1.18 × 109l./mole-sec, which is comparable with the diffusion-controlled rate of reaction between small molecules. The rate of reaction between segment radicals is fivefold larger than the polymer-polymer termination when transfer predominates. 相似文献
9.
《液相色谱法及相关技术杂志》2012,35(2):197-226
Abstract The nature of the averaging process in the analysis of gel permeation chromatograms was examined for cases where the molecules in the detector cell of the apparatus were of different molecular weight and of the same molecular weight. When the molecules have the same molecular weight, the hydrodynamic volume (1), [?]M, averaged across a chromatogram was found to become KMa+1 for any molecular weight average at the elution volume corresponding to that average. [η] is intrinsic viscosity, M is molecular weight, and K and a are the appropriate Mark-Houwink constants. Thus when size separation is by molecular weight, the universal GPC calibration functions include KMn a+1 where Mn is the number average molecular weight. Cellulose nitrate and poly(oxypropylene) were analyzed using three sets of columns and two GPC instruments. KMn a+1, KMw a+1, and [η]Mw were found to represent the hydrodynamic volume since these functions fell on the universal calibration plot for nearly nono-disperse polystyrene standards. The function [η]Mn was displaced from the polystyrene universal calibration plot by factor which equaled Mw/Mn. The slopes and intercepts of the universal calibration plots were found to be completely consistent with the slopes and intercepts of the molecular weight calibration plots showing that the Mark-Houwink constants were correct. Intrinsic viscosity - molecular weight relations were presented for 12.0–12.6%N cellulose nitrate and for low molecular weight poly(oxypropylene), the latter relation being a correction of that of Sholtan and Lie (18). 相似文献
10.
J. Dahelka I. Kssler V. Boh
kov 《Journal of polymer science. Part A, Polymer chemistry》1976,14(2):287-298
Two samples of cellulose (molecular weight 2.97 × 105 and 1.25 × 105) were transformed into carbanilates (CTC) which were then fractionated by the elution method at a constant composition of the acetone-water elution mixture with the column temperature gradually increasing from ?30°C to 30°C, and by the GPC method in acetone and tetrahydrofuran. Tetrahydrofuran appeared to be a more suitable solvent. The molecular weights of fractions obtained by the elution fractionation were determined by the light-scattering method in tetrahydrofuran. The width of fractions was determined by the GPC method (average M w/M n = 1.37); the [η] values and the Mark-Houwink constants (K = 5.3 × 10-3, a = 0.84) for tetrahydrofuran at 25°C were determined. The calibration curve for the GP method was constructed by means of the fractions thus obtained; it was demonstrated that the universal calibration curve according to Benoit can also be used. It was demonstrated that the molecular weight distribution of cellulose can be conveniently determined by conversion into CTC followed either by the elution fractionation (for preparative purposes) or by fractionation by the GPC method (for analytical purposes). 相似文献
11.
Mephenesin is being used as a central‐acting skeletal muscle relaxant. Oxidation of mephenesin by bis(hydrogenperiodato)argentate(III) complex anion, [Ag(HIO6)2]5?, has been studied in aqueous alkaline medium. The major oxidation product of mephenesin has been identified as 3‐(2‐methylphenoxy)‐2‐ketone‐1‐propanol by mass spectrometry. An overall second‐order kinetics has been observed with first order in [Ag(III)] and [mephenesin]. The effects of [OH?] and periodate concentration on the observed second‐order rate constants k′ have been analyzed, and accordingly an empirical expression has been deduced: k′ = (ka + kb[OH?])K1/{f([OH?])[IO?4]tot + K1}, where [IO?4]tot denotes the total concentration of periodate, ka = (1.35 ± 0.14) × 10?2M?1s?1 and kb = 1.06 ± 0.01 M?2s?1 at 25.0°C, and ionic strength 0.30 M. Activation parameters associated with ka and kb have been calculated. A mechanism has been proposed to involve two pre‐equilibria, leading to formation of a periodato‐Ag(III)‐mephenesin complex. In the subsequent rate‐determining steps, this complex undergoes inner‐sphere electron transfer from the coordinated drug to the metal center by two paths: one path is independent of OH? whereas the other is facilitated by a hydroxide ion. In the appendix, detailed discussion on the structure of the Ag(III) complex, reactive species, as well as pre‐equilibrium regarding the oxidant is provided. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 440–446, 2007 相似文献
12.
Mitsuru Ueda Masahiko Yazawa Toshiyuki Suzuki Charles U. Pittman 《Journal of polymer science. Part A, Polymer chemistry》1986,24(12):3177-3189
Methylthiomethyl methacrylate (MtMA) was synthesized and homopolymerized in solution. The poly(MtMA) is readily soluble in benzene, acetone, tetrahydrofuran, and methylene chloride at room temperature. The values of K and a in the Mark–Houwink equation, [η] = KMa, were found to be K = 2.88 × 10–5 and a = 0.75 when M = Mw. The glass transition temperature of poly(MtMA) was observed to be 72°C by thermomechanical analysis. Intramolecular anhydride formation occurred when poly(MtMA) was heated to 250–300°C. The kinetics of MtMA homopolymerization was investigated in benzene, using azobisisobutyronitrile as initiator. The rate of polymerization Rp was expressed by Rp = k[AIBN]0.5[MtMA]1.05 and the overall activation energy was calculated to be 75.7 kJ/mol. The relative reactivity ratios of MtMA in styrene copolymerizations (r1 = 0.33, r2 = 0.55) were obtained. Applying the Q-e scheme led to Q = 1.07 and e = 0.51 for MtMA. 相似文献
13.
Catalytic activity of catalase (CAT) immobilized on a modified silicate matrix to mediate decomposition of meta-chloroperoxibenzoic
acid (3-CPBA) in acetonitrile has been investigated by means of quantitative UV-spectrophotometry. Under the selected experimental
conditions, the kinetic parameters: the apparent Michaelis constat (K
M
), the apparent maximum rate of enzymatic reaction (V
max
app
), the first order specific rate constants (k
sp
), the energy of activation (E
a
) and the pre-exponential factor of the Arrhenius equation (Z0) were calculated. Conclusions regarding the rate-limiting step of the overall catalytic process were drawn from the calculated
values of the Gibbs energy of activation ΔG*, the enthalpy of activation ΔH*, and the entropy of activation ΔS*. 相似文献
14.
K. N. Ninan K. B. Catherine K. Krishnan 《Journal of Thermal Analysis and Calorimetry》1990,36(3):855-867
Hydroxyl terminated polybutadiene prepared by free radical polymerization was fractionated by a solvent-nonsolvent precipitation method. The fractions were characterized by gel permeation chromatography for their molecular weight averages (¯M
n,¯Mw and¯M
z) and dispersities. The kinetic parameters, viz., energy of activationE and preexponential factorA for the thermal decomposition of the fractions were computed from their TG data, using four nonisothermal integral equations. Quantitative correlations between the kinetic constants and the molecular weight parameters were derived for the first time for HTPB as:E (or InA)=k
1–k2/¯Mn (or ¯M
w or ¯M
z) and the trend is explained on the basis of the kinetic compensation effect.
We thank Dr. K. V. C. Rao, Mr. M. R. Kurup and Director, VSSC for their kind permission to publish this paper. 相似文献
Zusammenfassung Mittels eines Löser-Nichtlöserverfahrens wurde ein durch Radikalpolymerisation hergestelltes, Hydroxyl-endständiges Polybutadien fraktioniert. Das mittlere Molekulargewicht (¯M n, ¯Mw and¯M z) und der Dispersionsgrad der einzelnen Fraktionen wurden durch Gelchromatograpie charakterisiert. Die kinetischen Parameter, d.h. die Aktivierungsenergie E und der präexponentielle FaktorA wurden auf der Basis der TG Daten unter Zuhilfenahme von vier nichtisothermen Integralgleichungen berechnet. Zum ersten Male konnte für HTPB ein quantitativer Zusammenhang zwischen den kinetischen Konstanten und den Molekulargewichtparametern gefunden werden:E (order InA)=k 1–k2/¯Mn (order¯M w order¯M z). Diese Tendenz wurde auf der Basis des kinetischen Kompensationseffektes gedeutet.
We thank Dr. K. V. C. Rao, Mr. M. R. Kurup and Director, VSSC for their kind permission to publish this paper. 相似文献
15.
V. N. Tsvetkov P. N. Lavrenko S. V. Bushin 《Journal of polymer science. Part A, Polymer chemistry》1984,22(11):3447-3486
The theories of hydrodynamic properties of macromolecules in solution leading to an invariant relationship between the values of the intrinsic viscosity, [η], the molecular weight, M, and the translational friction coefficient of the molecule, f, have been considered. The review of experimental data comprising as much as about 2000 fractions of various polymers suggests that for all flexible-chain and moderately rigid-chain molecules the hydrodynamic parameter A0 = kη0(M[η]/100)1/3f?1 is actually an invariant independent of the chain length and the thermodynamic strength of the solvent and for moderately polydisperse samples also independent of the degree of their polydispersity. For polymers with very rigid chains the parameter A0 has a high value over the experimentally investigated range of M. These conclusions make it possible to recommend the use of the following average experimental values of the invariant A0 for the determination of M of polymers from the values of [η] and f: for flexible-chain and synthetic polymers with moderately high chain rigidity (3.2 ± 0.2) · 10?10, for polymers with high chain rigidity (3.7 ± 0.4) · 10?10, and for cellulose derivatives and other polysaccharides with molecular dispersity of nonelectrolyte solutions (3.30 ± 0.30) · 10?10 erg deg?1 mol?1/3. The fact that the experimental value of A0 = 3.2 · 10?10 does not coincide with the value of A∞ = 3.8 · 10?10 erg deg?1 mol?1/3 predicted by the theories of translational friction and viscosity of macromolecules implies that the theoretical values of P∞ = 5.11 and Φ∞ = 2.8 · 1023 mol?1 are mutually incompatible and these theories require further development. 相似文献
16.
Eric Da Silva Cécile F. Rousseau Isabelle Zanella-Cléon Michel Becchi Anthony W. Coleman 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):53-59
Electrospray Ionization Mass Spectrometry (ESI/MS) has been used to determine the association constants (KAs) and binding stoichiometries for parent para-Sulphonato-calix[n]arenes and their derivatives with bovine serum albumin (BSA). KA values were determined by titration experiments using a constant concentration of protein. KA measurements were carried out in a methanol–formic acid solution. 5,11,17,23–tetra-Sulphonato-calix[4]arene (1a) and 25-mono-(2-aminoethoxy)-5,11,17,23-tetra-Sulphonato-calix[4]arene (1d) interact strongly with BSA showing 3 non-equivalent binding sites with KA1 = 7.69 × 105 M−1, KA2 = 3.85 × 105 M−1, KA3 = 0.33 × 105 M−1 and KA1 = 1.69 × 105 M−1, KA2 = 2.94 × 105 M−1, KA3 = 0.60 × 105 M−1, respectively. The strength of the interactions between the calixarene and BSA is inversely proportional to the size of macrocyclic
ring: n = 4 > n=6>>n=8. 相似文献
17.
Mohammad R. Kasaai Joseph Arul Grard Charlet 《Journal of Polymer Science.Polymer Physics》2000,38(19):2591-2598
The intrinsic viscosity–molecular weight relationship for chitosan was determined in 0.25 M acetic acid/0.25M sodium acetate. Chitosan samples with a degree of acetylation (DA) between 20 and 26% were prepared from shrimp‐shell chitosan by acid hydrolysis (HCl) and oxidative fragmentation (NaNO2). Absolute molecular weights were measured by light scattering and membrane osmometry. Size exclusion chromatography (SEC) was used to determine average molecular weights (Mn, Mv, and Mw) and polydispersity. The following Mark–Houwink–Sakurada equation (MHS) is proposed for chitosan of Mw in the range of 35–2220 kDa: The value of the MHS exponent a suggests that chitosan behaves as a flexible chain in this solvent. Examination of MHS constants obtained in this work and those available in the literature with other solvents indicates that a and K are inversely related and that they are influenced by DA, and pH and ionic strength of the solvent. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2591–2598, 2000 相似文献
18.
Enzymes play vital roles in life processes. Almost all biochemical reactions are mediated by enzymes. The rate constants of
enzyme kinetics are the most important parameters for the reactions catalyzed by enzymes. In 1902, Adrian Brown proposed a
simple single-substrate-single-product model which contains only three rate constants k
1, k
−1 and k
2. So far, biologists can measure the Michaelis constant K
M
and the catalytic constant k
cat
, which actually is equal to k
2, according to Michaelis–Menten equation. Using temperature jump method or transient state kinetics, k
1, k
−1 and k
2 can be determined. However, these methods are complicated. In this article, we design a novel simple method that could determine
the rate constants k
1 and k
−1 based on knowing k
cat
and K
M
. Our numerical experiments show that the three rate constants can be calculated rather precisely. Hence, we believe that
biochemists could design experiments to measure the rate constants based on our method.
This work was partially supported by the National Natural Science Foundation of China (NSFC) under Grant No. 10771206 and
partially by 973 project (2004CB318000) of P. R. China. 相似文献
19.
The reduction of Fe(CN)5L2? (L = pyridine, isonicotinamide, 4,4′‐bipyridine) complexes by ascorbic acid has been subjected to a detailed kinetic study in the range of pH 1–7.5. The rate law of the reaction is interpreted as a rate determining reaction between Fe(III) complexes and the ascorbic acid in the form of H2A(k0), HA?(k1), and A2? (k2), depending on the pH of the solution, followed by a rapid scavenge of the ascorbic acid radicals by Fe(III) complex. With given Ka1 and Ka2, the rate constants are k0 = 1.8, 7.0, and 4.4 M?1 s?1; k1 = 2.4 × 103, 5.8 × 103, and 5.3 × 103 M?1 s?1; k2 = 6.5 × 108, 8.8 × 108, and 7.9 × 108 M?1 s?1 for L = py, isn, and bpy, respectively, at μ = 0.10 M HClO4/LiClO4, T = 25°C. The kinetic results are compatible with the Marcus prediction. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 126–133, 2005 相似文献
20.
Ultrasound‐mediated atom transfer radical polymerization (sono‐ATRP) in miniemulsion media is used for the first time for the preparation of complex macromolecular architectures by a facile two‐step synthetic route. Initially, esterification reaction of sucrose or lactulose with α‐bromoisobutyryl bromide (BriBBr) is conducted to receive multifunctional ATRP macroinitiators with 8 initiation sites, followed by polymerization of n‐butyl acrylate (BA) forming arms of the star‐like polymers. The brominated lactulose‐based molecule was examined as an ATRP initiator by determining the activation rate constant (ka) of the catalytic process in the presence of a copper(II) bromide/tris(2‐pyridylmethyl)amine (CuIIBr2/TPMA) catalyst in both organic solvent and for the first time in miniemulsion media, resulting in ka = (1.03 ± 0.01) × 104 M?1 s?1 and ka = (1.16 ± 0.56) × 103 M?1 s?1, respectively. Star‐like macromolecules with a sucrose or lactulose core and poly(n‐butyl acrylate) (PBA) arms were successfully received using different catalyst concentration. Linear kinetics and a well‐defined structure of synthesized polymers reflected by narrow molecular weight distribution (Mw/Mn = 1.46) indicated 105 ppm wt of catalyst loading as concentration to maintain controlled manner of polymerization process. 1H NMR analysis confirms the formation of new sugar‐inspired star‐shaped polymers. 相似文献