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1.
Synthesis and characterization of vinyl silane modified imidazole copolymer as a novel corrosion inhibitor 总被引:1,自引:0,他引:1
For a novel corrosion inhibitor for copper, the free radical copolymerization of vinyl imidazole (VI) and vinyl trimethoxy
silane (VTS) was carried out in benzene at 68 °C using azobisisobutyronitrile (AIBN) as an initiator. The reactivity ratios
of the two monomers were determined from instantaneous composition diagram: r
VI = 3.22 and r
VTS = 0. Thermal stability of poly(VI-co-VTS) depended on VTS mole fraction in the feed rather than the molecular weight of the
copolymer, due to the disiloxane bond linkages formed during heating.
Received: 21 October 1996/Revised: 9 December 1996/Accepted: 12 December 1996 相似文献
2.
To the purpose of studying the effect of composition on the glass transition temperature (Tg) of a series of polymer electrolytes
based on blends of polyethylene oxide (PEO), poly(octafluoropentoxytrifluoroethoxy)phosphazene (PPz) and poly(epichlorhydrine),
a mathematical model was applied to results obtained through DSC determination using seven ternary blends selected by an experimental
design. The parameters of the model were chosen by means of stepwise linear regression method. The final model proved to be
appropriate (R2 = 0.997; s = 0.99 K) to predict the Tg values. From a structural point of view it was found that the lowest Tg values were
obtained for the blends containing the smallest PECH portion.
Received: 18 November 1996/Revised: 2 December 1996/Accepted: 3 December 1996 相似文献
3.
Poly(3-(t-butoxycarbonyl)-1-vinylcaprolactam) (PBCVC) was synthesized and evaluated as a potential deep UV photoresist. The synthesized
polymer has excellent transmittance at 248 nm (absorbance = 0.018 μm−1). In addition, PBCVC possesses good thermal stability up to 220 °C and a high glass transition temperature (174 ∼ 190 °C).
The thermal deprotection of side chain ester groups of PBCVC occurs at 220 °C, whereas in the presence of acid the cleavage
of the t-butyl ester groups of PBCVC begins at about 80 °C, and followed by evolution of carbon dioxide at about 150 °C. Deprotection
of PBCVC gave the corresponding polymer, poly(1-vinylcaprolactam-3-carboxylic acid). The contrast of the PBCVC resist system
was not deteriorated with the post-exposure delay (PED) time.
Received: 2 September 1996/Revised: 18 December 1996/Accepted: 20 December 1996 相似文献
4.
Katsuyuki Tsuda Wataru Hirahata Kazuaki Yokota Toyoji Kakuchi Takashi Ishizone Akira Hirao 《Polymer Bulletin》1997,39(2):173-178
The radical polymerizations of 2-, 3-, and 4-(trimethylsilylethynyl)styrenes (1 a – c) and copolymerizations of 1 a – c (M1) with styrene (M2) have been studied. Copolymerization parameters were determined as r1 = 1.22 and r2 = 0.54 for 1 a, 1 = 1.10 and r2 = 0.90 for 1 b, and r1 = 1.42 and r2 = 0.38 for 1 c. The deprotection of the trimethylsilyl groups in poly[(trimethylsilylethynyl)styrene] (2 a – c) and poly[(trimethylsilylethynyl)styrene-co-styrene] (4 a – c) using (C4H9)4NF smoothly proceeded to yield poly(ethynylstyrene) (3 a – c) and poly(ethynylstyrene-co-styrene) (5 a – c), respectively, which underwent curing reactions at elevated temperature to form crosslinking polystyrenes.
Received: 31 March 1997/Revised: 2 June 1997/Accepted: 3 June 1997 相似文献
5.
Helena Valentová Miroslav Kašpar Věra Hamplová Karel Bouchal Michal Ilavský Antonín Sikora Daniel Froelich René Muller 《Polymer Bulletin》1997,38(2):219-226
The dynamic mechanical behaviour of random copolymers of LC monomer-1-(hexyloxycarbonyl)ethyl 4-[4-(methacryloyloxy)benzoyloxy]benzoate
(HB) and octyl methacrylate (OMA) was studied in the main transition and flow regions. Even though the aliphatic end groups
of the side chain of HB and OMA are roughly the same, the T
g temperature of poly(HB) is ∼ 80 K higher than that of poly(OMA); this fact is due to the presence of the stiff phenyl benzoate
mesogenic group in the side chain of HB. With increasing content of OMA in the copolymer the superimposed curves of the storage
G′
p and loss G′′
p moduli at a constant temperature shift towards shorter frequencies. It has been shown that this shift is mainly due to an
increase of the free volume in the copolymers with increasing content of OMA. While HB monomer shows liquid crystalline (LC)
properties, its polymer (poly(HB)) and random copolymers with OMA show only isotropic thermal behaviour because no flexible
spacer is present in the side chain of HB which would decouple the main chain and mesogenic group motions. This means that
neither the homopolymer of HB, nor its copolymers with a flexible comonomer retain the LC properties of the starting LC monomer,
HB.
Received: 26 September 1996/Revised: 7 November 1996/Accepted: 7 November 1996 相似文献
6.
Three poly(methyl methacrylate-co-2-bromoethyl methacrylate) samples were prepared. The bromine groups in the copolymers
were converted to azide groups followed by reaction with fullerene (C60) to afford fullerene-containing polymethacrylates. The glass transition temperatures (Tgs) and heat capacity changes (ΔCp) at Tg of these polymers were measured by differential scanning calorimetry. With increasing fullerene content in the polymethacrylate,
the Tg value increases while the ΔCp value decreases. The incorporation of fullerene improves the thermal stability of the polymethacrylate as shown by thermogravimetric
analysis.
Received: 25 February 1997/Revised: 12 May 1997/Accepted: 13 May 1997 相似文献
7.
Xiaoqing Liu Bo Chen Kang Zhou Jianping Deng Wantai Yang 《Journal of Polymer Research》2011,18(2):217-224
Five achiral N-propargylamide monomers with various phenyl-based substitutents, [HC ≡ CCH2NHCOR, R for M1: C6H4CH3; M2: C6H4CH2CH3; M3: C6H4(CH2)2CH3; M4: C6H4(CH2)3CH3; M5: C6H4C(CH3)3], were synthesized and polymerized with a rhodium catalyst, (nbd)Rh+B-(C6H5)4 (nbd = 2,5-norbornadiene). The corresponding five homopolymers were obtained in high yields of 90–95% and with moderate molecular
weights (M
n ≥ 10 000). All the polymers possessed high cis contents (≥95%). Poly(1)–poly(3) exhibited UV-vis absorption peaks at approx.
350 nm, which indicates that the three polymers formed helical conformations, while no UV-vis absorption peaks could be observed
in poly(4) and poly(5) in the wavelength range of 320–500 nm, demonstrating that these two polymers could not adopt helical
structures under the examined conditions. To confirm the helical structures formed in poly(1)–poly(3), a chiral monomer, M6,
was utilized to copolymerize with M2, which was used as the representative for M1−M3. M6 was utilized since its polymer could
form stable helices under suited conditions. The resulting copolymers exhibited remarkable CD effects, however, the maximum
wavelength in the copolymers varied remarkably, mainly depending on the composition of the copolymers. It is concluded that
in the formation of ordered helical conformations, the substitutents of varied bulk led to different steric repulsion and
varied synergic effects among the neighboring pendent groups. 相似文献
8.
Hydrogenated segmented poly[butadiene-block-(styrene-block-butadiene)n] block copolymers, which were developed by use of a polymeric iniferter technique, were tested on their compatibilizing effectiveness
for (10/90) LDPE/PS blends. They were found to be effective compatibilizers for this mixture, already giving a pronounced
improvement in both tensile strength and strain of the blend at block copolymer concentrations of one percent. A concentration
of five weight percent of segmented block copolymer provided a tenfold improvement in blend toughness. The effectiveness of
the segmented block copolymers was found be dependent on the block copolymer composition. Block copolymer compositions of
close to 50 : 50 EB : PS gave the best results.
Received: 23 September 1996/Revised: 4 November 1996/Accepted: 7 November 1996 相似文献
9.
The characterization of a block copolymer consisting of blocks of tetrahydrofuran, THF, and methyl methacrylate, MMA, was
attempted with the aid of liquid chromatography, LC, at the critical adsorption point, CAP. The conditions applying to the
CAP at 30 °C for the homopolymers are: PTHF: eluent composition: THF : acetonitrile = 50 : 50, w/w; column: Nucleosil C18. PMMA: eluent composition: THF : n-hexane = 81.8 : 18.2, w/w; column: bare silica gel. The presence of homo PTHF and of homo
PMMA in the crude block copolymer was evidenced. Moreover, chromatography at the CAP for PMMA showed that the block copolymer
contains multiblock (triblock) fractions. The formation of triblock copolymer is expected when the polymerization of MMA is
terminated (partially) by combination. In conclusion, LC at the CAP is a powerful tool to characterize block copolymers regarding
the presence of homopolymer and multiblock (triblock) fractions.
Received: 13 February 1997/Revised: 18 March 1997/Accepted: 24 March 1997 相似文献
10.
A series of poly(benzophenoneimide)s (Cm-BP-PIs) having n-alkyloxymethyl side chains (−CH2O-n-CmH2m+1, m = 4, 6, 8) have been examined by X-ray diffraction, differential scanning calorimetry (DSC) and polarizing optical microscopy.
The samples showed basically two phase transitions and both transition temperatures decreased with increasing side chain length.
The first transitions were ascribed to glass transitions and the second ones were assigned to liquid crystal-to-isotropic
transitions. Eicosane (n-C20H42) which is chemically very similar to the side chain was miscible with the side chains of C8-BP-PI, which induced depression of the glass transition temperature.
Received: 17 February 1997/Revised: 1 April 1997/Accepted: 4 April 1997 相似文献
11.
4-{1′-(2″-Methacryloyloxyethoxy)-5′-naphthyliminomethylidene}-4′-nitro-stilbene 6 was prepared by the reactions of methacryloyl chloride with 4-{1′-(2″-hydroxyethoxy)-5′-naphthyliminomethylidene}-4′-nitrostilbene
5. Compound 5 was synthesized from 4′-methyl-4-nitrostilbene by several reaction steps. Monomer 6 was polymerized with DTBP as a radical initiator to obtain polymer with 4-(1′-oxy-5′-naphthyliminomethylidene)-4′-nitrostilbene,
which is presumably effective chromophore for second-order nonlinear optical applications in the side chain. The resulting
polymethacrylate 7 showed a thermal stability up to 300 °C in TGA thermogram, and the Tg value obtained from DSC thermogram was 120 °C, which is acceptable for NLO device applications.
Received: 14 October 1996/Accepted: 11 December 1996 相似文献
12.
While the rheological behavior at the gel point (GP) itself is well known, many questions remain about the approach to the
gel point (from either side). For studying this phenomenon, rheological experiments were performed on crosslinked polydimethylsiloxanes
(PDMS) and characteristic patterns in the relaxation behavior were abstracted into a phenomenological model for the relaxation
time spectrum. The well known power law with slope-n and cutoff at the longest relaxation time λ
max governs the relaxation near the gel point. Beyond the gel point, an additional box-like contribution appears in the spectrum.
The relaxation exponent n decreases with increasing extent of crosslinking. The longest relaxation time λ
max and equilibrium modulus Ge show power-law scaling with the distance from the gel point, |p − pc|. For samples with imbalanced stoichiometric ratios r ≥ 1, the function n (p − pc) is independent of r. Samples with strong crosslinker deficiency (r = 0.5) exhibit a different functional form for n (p − pc) from those with r ≥ 1. The power law relaxation with decreasing n in the terminal zone was found previously for a different
crosslinking system. It seems to be a common pattern for partially crosslinked materials from polymeric precursors.
Received: 11 December 1997/Revised version: 18 December 1997/Accepted: 18 December 1997 相似文献
13.
The aim of this study is to examine the influence of crosslinking density on 5-Fluorouracil release from poly(2-hydroxyethyl
methacrylate) (PHEMA) hydrogels crosslinked with 1,1,1-trimethylolpropane trimethacrylate (TPT). PHEMA hydrogels were synthesized
by bulk polymerization with different proportions of TPT (1 – 10 wt%) as crosslinker agent and ammonium persulphate as initiator,
enabling polymerization in the feed mixture in the presence of water. As a result, 5-FU could be trapped by including it as
a sodium salt in the feed mixture of polymerization. Discs with 5-FU loads between 1 – 16 mg/disc were obtained. Swelling
and 5-FU release kinetics studies were carried out in saline solution at 310 K. The diffusion studies were in accordance with
Fick's second law during the initial stages, enabling the diffusion coefficients of the process to be determined. The time
required for discs to reach total 5-FU release was between 35 h and 160 h and was a function of crosslinking density of the
gels and 5-FU load of the discs.
Received: 12 July 1996/Revised version: 8 October 1996/Accepted: 15 October 1996 相似文献
14.
Liqiang Cui Junsheng Yu Yinghai Lv Guijiang Li Shixue Zhou 《Journal of Polymer Research》2012,19(6):9881
In this study, syndiotactic-rich poly(methyl methacrylate) (PMMA) is obtained by using a soluble nickle acetylacetonate [Ni(acac)2] and modified methylaluminoxane (MMAO-3A) catalyst system under modest polymerization conditions. The main purpose of this
work is concerned with the study of previous conflicting stereospecificity data. Types of MAO, temperature of polymerization,
MAO/Ni(acac)2 (Al/Ni) mole ratio, and various solvents have been investigated in the MMA polymerization. Particularly, high syndiotactic
PMMA [(rr) > 91 %] has been obtained when MMAO-3A is used as cocatalyst with Al/Ni ratio of ca. 50 or polymerization temperature ca. 0 °C. As expected, the prepared syndiotacticity-rich PMMA has a higher glass transition temperature (T
g) within 120 ~ 127 °C. The details of the polymerization mechanism, especially in relation to the stereoregularity problems
are under investigation. 相似文献
15.
Homo- and copolymerizations of 1,5-hexadiene with ethene and styrene using halfsandwich metallocene catalyst Me2Si(Me4Cp)(N-tert.-butyl)TiCl2/MAO (Cp = cyclopentadienyl, Me = methyl, MAO = methylalumoxane) were investigated. According to 13C-NMR spectroscopic microstructure analysis, cyclopolymerization of 1,5-hexadiene afforded randomly distributed cis- and trans-cyclopentane
rings in the homo- and copolymer backbone. 1,5-hexadiene incorporation reached 52 mol-%. The ratio of vinyl side chains to
cyclopentane rings was controlled by 1,5-hexadiene concentration, where low 1,5-hexadiene concentration promoted cyclopolymerization.
Copolymer glass transition temperatures increased with increasing content of cyclic units in the backbone. Styrene was used
successfully as termonomer in ethene/1,5-hexadiene polymerization, resulting in a semicrystalline terpolymer with cyclic and
styrenic units in the polymer backbone.
Received: 5 September 1996/Accepted: 11 November 1996 相似文献
16.
Won -Ki Lee Jeong -Sik Yoon Keiji Tanaka Noriaki Satomi Xiqun Jiang Atsushi Takahara Chang -Sik Ha Tisato Kajiyama 《Polymer Bulletin》1997,39(3):369-376
Summary. The relationships between lateral force and viscoelastic properties of amorphous polymer surfaces with Tg's lower and higher
than room temperature (295 K, RT) and their blend systems have been studied on the basis of lateral force microscopic (LFM)
measurement. Under the conditions of scanning rate of 102–105 nm sec-1, normal load of 5 nN and RT, the lateral forces of poly(methyl methacrylate) (PMMA) and polyisoprene (PI) homopolymers with
Tg's fairly higher and lower than RT, respectively, did not depend on the scanning rate. Whereas, the lateral force of poly(methyl
acrylate) (PMA) with Tg ≤ RT decreased with an increase in the scanning rate. Also, poly(vinyl acetate) (PVAc) with Tg ≥ RT
showed slight dependence on the scanning rate. The scanning rate dependence of lateral force was similar to the frequency
dependence of mechanical loss modulus. The results indicate that the magnitude of lateral force strongly depends on the state
of thermal molecular motion. The lateral force-viscoelastic properties of miscible polymer blends was also investigated by
LFM.
Received: 30 June 1997/Revised: 24 July 1997/Accepted: 29 July 1997 相似文献
17.
The solution resulting from reaction between Ph2Zn and H2O in benzene was used by itself and separated in soluble and insoluble fractions to initiate styrene polymerization. The soluble
fraction produced the largest polymer conversion while the insoluble was reponsible of the highest molecular weights. Resulting
polystyrenes were atactic but up to 80 – 85% syndiotactic triads were detected by 1H-NMR analysis. Polystyrene obtained using benzene as solvent showed a low crystalline content while the polymer obtained
using dichloromethane did not produce any crystalline fraction.
Received: 10 December 1996/Revised: 15 April 1997/Accepted: 18 April 1997 相似文献
18.
Olivier Lambert Simone Reutenauer Guy Hurtrez Gérard Riess Philippe Dumas 《Polymer Bulletin》1998,40(2-3):143-149
We describe the synthesis and the characterization of amphiphilic triarm star block copolymers based on polystyrene, poly(methyl
methacrylate), poly(ε caprolactone), poly(l lactide) and poly(ethylene oxide) blocks. This synthesis has been achieved by a new route consisting in 2 successive initiation
steps on a core molecule (a 1,1-diphenyl-ethylene derivative bearing a protected hydroxy function) located at the end of a
first block. Some results on adsorption onto TiO2 and micellization studies are given. Preliminary results on solid state indicate an increase of the miscibility of the different
incompatible blocks.
Received: 3 November 1997/Revised version: 1 December 1997/Accepted: 2 December 1997 相似文献
19.
Takakazu Yamamoto Mahmut Abla Takahisa Shimizu Dahrma Komarudin Bang-Lin Lee Eriko Kurokawa 《Polymer Bulletin》1999,42(3):321-327
Summary
Temperature dependent electrical conductivity of substituted polythiophenes (poly(3,4-ethylenedioxythiophene) PEDOTh and head-to-tail
type poly(3-alkylthiophene) HT-P3RTh) has been measured. The electrical conductivity (σ) of p-doped PEDOTh and HT-P3RTh obeys
equations of a type, ln σ= ln σo− (To/T)0.25, with the To value of about 105–107 K.
Received: 21 December 1998/Revised version: 8 February 1999/Accepted: 15 February 1999 相似文献
20.
Synthesis and optical properties of cocoon-like poly(methyl methacrylate) (CPM) particles in the size range of D
n
= 3.0–6.5 μm were studied. The synthesis of these anisotropic particles consists of two steps. The spherical poly(methyl
methacrylate) (PMA) particles (D
n
= 2.2–5.5 μm) cross-linked by 0.2–0.8 wt% ethylene glycol dimethacrylate (EGDMA) were prepared by dispersion polymerization,
using a combination of poly(vinyl pyrrolidone) (PVP) and sodium di-(2-ethylhexyl) sulfosuccinate (NaEHS) as a stabilizer in
94:840 water–methanol. Then, a suspension polymerization of 9:1 methyl methacrylate (MMA)/EGDMA in the presence of the PMA
particles as seed at 85 °C in water gave non-spherical, cocoon-like CPM particles, depending on the cross-linking densities
of PMA particles. The cocoon-like CPM particles (D
n,c
= 4.0 μm) showed the characteristic features of regular reflection, which can not be attained for conventional poly(methyl
methacrylate) particles with a spherical shape. The effects of seed PMA particles with different properties on the formation
of cocoon-like CPM particles and their regular reflection properties are described. 相似文献