Effect of the structure of latex particles on adhesion. Part I: Synthesis and characterization of structured latex particles of acrylic copolymers and their peel adhesion behavior

This is a series of articles that deals with fundamental aspects of the effects of the structure of latex particles of acrylic copolymers on their adhesion behavior. Specifically, relationship or analogy between rheological properties and adhesion performance of the acrylic copolymers was demonstrated. The first part of this series concerns the synthesis and characterization of latex particles with desired structures and compositions, and the experimental results of peel adhesion. The second part develops an analogy between the peel adhesion performance of the adhesives and rheological properties of the corresponding copolymers. The third part addresses the generalities and particularities of three major tests for adhesion: peeling, blistering, and spontaneous peeling. Three types of structured latex particles were synthesized by three different emulsion polymerization processes: the first type had a uniform composition over the entire particles with a glass transition temperature (T_g) varying between ?40°C and 0°C, depending upon the compositions of monomers involved in the copolymer; the second type was of core-shell structure. As for the third type, the composition of monomers varied gradually across the particle radii. The glass transition behavior and the dynamic mechanical properties in the solid state of the copolymers confirmed the structures of the corresponding latex particles. On the other hand, the peel adhesion performance of the films of these latex particles varied with the dynamic mechanical properties of the corresponding copolymers. This implies that a correlation could be found between the structure of the latex particles, dynamic mechanical properties in the solid state of the corresponding copolymers, and the peel adhesion performance of the adhesive films. ©1995 John Wiley & Sons, Inc.     

Associative organotin polymers. I. Symmetric trialkyltin fluorides: Synthesis and properties

Four novel symmetric tri-n-alkyltin fluorides were prepared. In this homologous series, melting point decreases with increase in the carbon chain length while an x-ray diffraction study shows an increase in amorphousness. ¹H-NMR spectra in cyclohexane, a nonpolar solvent in which these compounds form long polymeric chain, show a peak broadening effect due to high solution viscosity at very low solute concentration. Contrary to this, the spectra in CDCl₃, a polar solvent in which these compounds are monomeric, show well resolved and narrow peaks. IR frequencies for Sn? C vibrations have been assigned.     

Synthesis,rheology, and morphology of nylon‐11/layered silicate nanocomposite

Exfoliated nylon‐11/layered silicate nanocomposites were prepared via in situ polymerization by dispersing organoclay in 11‐aminoundecanoic acid monomer. The original clay was modified by a novel method with 11‐aminoundecanoic acid. In situ Fourier transform infrared spectroscopy results show that stronger hydrogen bonds exist between nylon‐11 and organoclay than that of between nylon‐11 and original clay. The linear dynamic viscoelasticity of organoclay nanocomposites was investigated. Before taking rheological measurements, the exfoliated and intercalating structures and the thermal properties were characterized using X‐ray diffraction, transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analysis. The results show that the clay was uniformly distributed in nylon‐11 matrix during in situ polymerization of clay with 4 wt % or less. The presence of clay in nylon‐11 matrix increased the crystallization temperature and the thermal stability of nanocomposites prepared. Rheological properties such as storage modulus, loss modulus, and relative viscosity have close relationship with the dispersion favorably compatible with the organically modified clay. Comparing with neat nylon‐11, the nanocomposites show much higher dynamic modulus and stronger shear thinning behavior. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2161–2172, 2006     

Poly(phenylene sulfide) magnetic composites. I. Relations of percolation between rheology,electrical, and magnetic properties

Poly(phenylene sulfide)/ferrosoferric oxide composites (PPS/Fe₃O₄) with various loading levels were prepared by melt compounding. The microstructure of composites was investigated using SEM and XRD. The rheological, electrical and magnetic properties were characterized respectively by the parallel plate rheometer, high resistance meter, and magnetometer. The results reveal that the Fe₃O₄ particles are well dispersed in the PPS matrix due to their nice affinity, which results in a weak strain overshoot at large amplitude oscillatory level. Both the rheological and the electrical responses of the composites show a typical percolation behavior. But the rheological percolation presents lower threshold (< 40 wt %) than that of electrical percolation (～ 50 wt %), which is attributed to the difference structure of the percolation network. The magnetic response, however, shows good linear relation with Fe₃O₄ loadings, indicating that the physical percolation has little influence on the magnetic properties. This is mainly due to the yielded long‐range magnetic interactions among Fe₃O₄ particles in the applied field, which are far stronger than those nonmagnetic physical interactions accounting for percolation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 233–243, 2008     

Branched polyacrylamides: Synthesis and effect of molecular architecture on solution rheology

Linear, star and comb-like polyacrylamides (PAM) have been prepared by atomic transfer radical polymerization (ATRP) in aqueous media at room temperature. The influence of the molecular architecture of PAM on the rheological properties in aqueous solution has been investigated. The well-known theory of increased entanglement density by branching for polymers in the melt can also be applied to polymers in the semi-dilute water solutions. We have demonstrated this by investigating the rheological properties of PAM of similar molecular weights with different molecular architectures. Interestingly, the solution viscosity of a comb PAM is higher compared to its linear and star analogues (both at equal span molecular weight, M_n,SPAN, and total molecular weight, M_n,tot). In addition to the pure viscosity, we also demonstrate that the visco-elastic properties of the polymeric solutions depend significantly on the molecular architecture of the employed PAM. The elastic response of water solutions containing comb PAM is more pronounced than for solutions containing either linear or star PAM at similar M_n,SPAN and M_n,tot. The obtained results pave the way for application of these polymeric materials in Enhanced Oil Recovery (EOR).     

Esterified porphyrazine complexes: Synthesis,characterization, aggregation behavior,and theoretical study

Magnesium porphyrazine having eight 5-hydroxypentylthio groups at the peripheral positions, was synthesized from 2,3-bis(5-hydroxypentylthio) maleonitrile. By the esterification reaction of octakis(5-hydroxypentylthio) porphyrazinato] Mg(II) with 3,4,5-trimethoxybenzoic acid in dicyclohexylcarbodiimide and toluene-p-sulfonic acid, esterified MgPz appending [5-thiopentyl 2-methoxy-4,6-bis(trifluoromethyl) benzoate] substituent was obtained. Further reaction of the metal-free porphyrazine with Co(II), Cu(II), Zn(II), and Fe(II) acetates have produced the metallo-porphyrazines. By reacting FePzCl with pyridine or pyrazine, the monomeric bis-axial and the oligomeric complexes were synthesized as the novel stable complexes, respectively. Their characterizations were performed by using elemental analysis, FT-IR, ¹H-NMR, ¹³C-NMR, mass and UV-Vis spectral data. The aggregation investigations carried out in different concentrations indicate that 3,4,5-trimethoxybenzyloxy-substituted porphyrazine compounds do not have any aggregation behavior in different concentrations. Quantum chemical computations were also done to the structural and electronic properties of target compounds.     

Enzymatic Synthesis of Oligopeptide. Part I. Papain-Catalyzed Synthesis of Dipeptide,Tripeptide and Tetrapeptide

Eighteen Z-X-Y-OTNB⁺ type dipeptides, four Z-Val-Cys(Bzl)-X-OTMB tripeptides and a tetrapeptide Z-Val-Cys(Bzl)-Cys(Bzl)-Asn-OTMB have been synthesized by papain-catalyzed reaction in reasonable yield after recystallization. Z-DL-Ala-OH has been resolved through papain-catalyzed synthesis of Z-L-Ala-Leu-OTMB with an optical purity as high as 98.6%. These results show that papain is a good catalyst for oligopeptide synthesis.     

Branching by reactive end groups. II. Synthesis,branching, and melt rheology of (meth)acrylate/p‐t‐butylphenol‐coterminated bisphenol a polycarbonates

(Meth)acrylate/p‐t‐butylphenol (PTBP)‐coterminated bisphenol A polycarbonates (PCs) were prepared by interfacial processes and subsequently were reacted at high temperatures (≥200 °C) to form new branched polymers. Two interfacial methods were used to prepare the precursor linear PCs, one with (meth)acryloyl chloride [(M)AC] and the other with (meth)acrylic acid [(M)AA]. Both processes involve phosgenation in the presence of catalytic amounts of triethylamine. The process that used (M)AC formed disproportionately large amounts of bisphenol A di(meth)acrylate, whereas the process using (M)AA required about 50% more phosgene to achieve high (M)AA conversions than typical interfacial PC processes. The branching of the acrylate/PTBP PCs occurred with heating at temperatures greater than or equal to 250 °C. The molecular weight and degree of branching depended on the mole ratio of the thermally reactive and nonreactive coterminators, the total amount of coterminators, and the reaction conditions. The functionality of the branch points formed appeared to be dependent on the acrylate concentration. The branching of the methacrylate/PTBP PCs required the presence of a free‐radical initiator and temperatures up to about 200 °C. The methacrylate end group was less effective than the acrylate on a molar basis in increasing the branched polymer molecular weight and degree of branching. The melt rheology of the branched acrylate/PTBP PCs showed the expected increase in low shear viscosity and shear rate sensitivity with increasing weight‐average molecular weight and acrylate‐end‐group concentration. Small changes in the total terminator concentration and, therefore, the linear precursor polymer molecular weight produced large effects in the low shear rate melt viscosity. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2340–2351, 2000     

Structure and rheology of hyperbranched and dendritic polymers. I. Modification and characterization of poly(propyleneimine) dendrimers with acetyl groups

Commercially available fourth and fifth generation poly(propyleneimine) (PPI) dendrimers were functionalized with acetyl chloride and deuterated acetyl chloride. Their solution properties in water and D₂O were measured with dilution viscometry, densitometry, rheology, and small‐angle neutron scattering (SANS) and compared to molecular modeling. Both the acetylated and PPI dendrimers exhibited Newtonian rheology in solution at all concentrations, but the functionalized dendrimers were less viscous than the nonacetylated dendrimers at an equal weight fraction (50 wt %). The acetylated dendrimers exhibited a pronounced structure peak in SANS, however, that was not evident for PPI in solution and a greatly enhanced solubility. This structure peak, evident at concentrations as low as 0.2 wt %, was evidence for long‐range electrostatic interdendrimer forces, which were screened by added salt. A quantitative agreement was obtained between the dilute‐limiting absolute scattering spectra of both the nonacetylated and acetylated dendrimers in solution with model calculations via a homogeneous spherical model and input parameters independently obtained from dilution viscometry or direct calculation. The combined measurements verified significant solvent penetration for both dendrimer types. The form factors measured in this manner were also in good quantitative agreement with the results of molecular dynamics simulations, which pointed to significant backfolding of the terminal groups. SANS and rheology measurements at higher concentrations suggested dendrimer clustering and interpenetration with increasing concentration, leading to less structure and lower viscosity than would be predicted from the dilute‐limiting behavior. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 857–873, 2000     

The induction plasma chemical reactor: Part I. Equilibrium model

A mathematical model is presented for the numerical simulation of the flow, temperature, and concentration fields in an rf plasma chemical reactor. The simulation is performed assuming chemical equilibrium. The extent of validity of this assumption is discussed. The system considered is the reaction of SiCl₄ and NH₃ for the production of Si₃N₄.     

Synthesis and Studies of Some Ketosulfones,Part I

New ketosulfones have been prepared. Their chemical composition and structure were proved by analytical and spectral methods. The kinetics of 1,4-addition of arenesulfinic acids to 1,3-diphenyl-2-nitropropenone and 3-nitro-4-phenyl-3-butene-2-on were studied by LC. The overall reaction is second order, while it is first order regarding each reagent and substrate. On the basis of the experimental results for the dependence of rate constants on the temperature and the influence of the substituents on the rate, a probable mechanism of the nucleophilic addition was suggested.     

Environmentally friendly acylaminocarboxylates yttrium (III) complexes: Synthesis,solubility and aggregation behavior

In order to investigate the effect of differences in amino acid alkyl chains, In order to investigate the effect of difference amino acid alkyl chains on the Rare earth complexes, the lipoaminic acids rare earth surfactant complexes of yttrium hexanoyl alaninc acid (Y(hex-ala)₃), yttrium octanoyl alaninc (Y(oct-ala)₃) and yttrium dodecanoyl alaninc acid (Y(dod-ala)₃) are synthesized by the reaction of C₉H₁₇NO₃, C₁₁H₂₁NO₃, C1₅H₂₉NO₃ with YCl₃, respectively. These complexes have been compared to the yttrium octanoate soap (Y(octnt)₃). At the same time, the formation of molecular glasses of these complexes are compared with the aggregation behavior in solution, evaluate properties as glass. Furthermore, the aggregation behavior of the above surfactant complexes in the pure solvent are studied using nuclear magnetic resonance (NMR) spectrometry, vapor pressure osmometry (VPO), electrical conductivity and Fourier Transform-Infrared spectroscopy (FT-IR). As results, these Y(III) complexes aggregate in the organic solvents system and tend to form aggregates. After the organic solvents evaporated, organic rare earth vitreous bodies was obtained.     

Hydrophobically modified poly(vinyl alcohol) using alkoxy‐substituted methyl gallate: Synthesis and rheology

Hydrophobically modified poly(vinyl alcohol) (HMPVA) polymers were synthesized by potassium t‐butoxide‐catalyzed reaction of PVA with methyl 3,4,5‐tris(n‐octyloxy) benzoate (MGC₈)/3,4,5‐tris(n‐dodecyloxy) benzoate (MGC₁₂) and 1,3‐propane sultone. The concentration of 1,3‐propane sultone was kept constant at 10 mol % and that of MGC₈ (2, 3, and 4 mol %)/MGC₁₂ (2 and 3 mol %) was varied to obtain HMPVAs with different hydrophobic contents. The incorporation of MGC₈/MGC₁₂ and 1,3‐propane sultone onto HMPVA was confirmed by NMR spectroscopy. Rheological properties of aqueous solutions also confirmed the presence of hydrophobic and charged functional groups on HMPVAs. In the semidilute regime, the specific viscosity of HMPVAs followed concentration scaling that is typical of polyelectrolytes. At higher concentrations, the HMPVA solutions with 3 and 4 mol % of MGC₈ exhibited large increase in specific viscosity. Oscillatory experiments on these solutions exhibited gel‐like behavior at polymer concentrations of 40–50 g/L. Confocal microscopy images of HMPVA with 4 mol % of MGC₈ clearly indicated the existence of microgels. The tendency of formation of microgels further increased with increasing chain length of the hydrophobe, that is, with MGC₁₂. These samples exhibited rheological behavior that is typical of soft solids and was therefore probed by the strain‐rate frequency superposition technique reported recently in the literature. HMPVAs with improved rheological properties show potential applications as thickeners in cosmetic creams, lotions and as drug carriers in pharmaceutical formulations. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1054–1063, 2010     

中孔沸石新材料MCM－41──Ⅰ．合成、酸性及稳定性

中孔沸石新材料ＭＣＭ－４１──Ⅰ．合成、酸性及稳定性赵修松，王清遐，徐龙伢，谢紊娟（中国科学院大连化学物理研究所，大连１１６０２３）李新生（中国科学院大连化学物理研究所催化基础国家重点实验室，大连１１６０２３）关键词ＭＣＭ－４１沸石，合成，酸性，稳定...     

Oil Base Mud. Part I: Synthesis of Some Local Surfactants Used as Primary Emulsifiers for Oil Base Mud and Evaluation of Their Rheology Properties

Six oil soluble nonionic surfactants with different HLBs have been prepared. Their HLBs situate between 3.9 and 6.7. Transesterification was carried out for glycerol and triethanol amine with oleic acid at different moles to obtain six emusilifiers. They named glycerol momooleate (I), glycerol diooleate (II), glycerol trioleate (III), triethanol amine mono-, di- and tri-oleate (IV), (V,) and (VI). The chemical structure was confirmed using; the elemental analysis, FTIR and ¹HNMR. They were evaluated as a primary emulsifiers (PE) for thdrilling fluids (oil base mud) comparing with a currently used primary emulsifier (Fc). The water in oil base mud (w/o emulsions) was prepared. The concentration of emulsifiers and their HLB exhibited interesting rheology properties including shear-thinning behavior, yield value, viscoelastic effects, thixtropy, gel strength, and filtration loss. The rheology properties of such emulsions strongly depended on the average size distribution of the dispersed droplets that could be varied both with the bulk concentration and HLB value of the emulsifiers. The interfacial and surface properties of these emulsifiers suggest that the droplet size of the dispersed phase and bulk concentration are strongly related to the HLB value of emulsifiers. The w/o emulsion (mud formulation) stability is sensitive to the droplet size of the dispersed phase and HLB value of the used emulsifier. The results were discussed on the light the chemical structure of the primary emulsifiers and the emulsion ingredients.     

Copper(I) cyanide networks: synthesis, structure, and luminescence behavior. Part 2. Piperazine ligands and hexamethylenetetramine

A variety of photoluminescent, and in some cases thermochromic, metal-organic networks of CuCN were self-assembled in aqueous reactions with amine ligands: (CuCN) 2(Pip) ( 1a), (CuCN) 20(Pip) 7 ( 1b), (CuCN) 7(MePip) 2 ( 2), (CuCN) 2(Me 2Pip) ( 3a), (CuCN) 4(Me 2Pip) ( 3b), (CuCN) 7(EtPip) 2 ( 4), (CuCN) 4(Et 2Pip) ( 5), (CuCN) 3(BzPip) 2 ( 6a), (CuCN) 5(BzPip) 2 ( 6b), (CuCN) 7(BzPip) 2 ( 6c), (CuCN) 4(BzPip) ( 6d), (CuCN) 2(Bz 2Pip) ( 7), (CuCN)(Ph 2CHPip) ( 8a), (CuCN) 2(Ph 2CHPip) ( 8b), (CuCN) 3(HMTA) 2 ( 9a), (CuCN) 5(HMTA) 2 ( 9b), and (CuCN) 5(HMTA) ( 9c) (Pip = piperazine, MePip = N-methylpiperazine, Me 2Pip = N, N'-dimethylpiperazine, EtPip = N-ethylpiperazine, Et 2Pip = N, N'-diethylpiperazine, BzPip = N-benzylpiperazine, Bz 2Pip = N, N'-dibenzylpiperazine, Ph 2CHPip = N-(diphenylmethyl)piperazine, and HMTA = hexamethylenetetramine). New X-ray structures are reported for 1b, 2, 3b, 4, 5, 6a, 6d, 7, 8b, 9b, and 9c. An important structural theme is the formation of (6,3) (CuCN) 2(piperazine) sheets with or without threading of independent CuCN chains. Strong luminescence at ambient temperature is observed for all but complexes 6 and 7. All luminescent compounds show a broad emission band in the blue region at about 450 nm attributable to metal-to-ligand charge transfer behavior based on the large Stokes shift between excitation and emission maxima. 3, 8, and 9 are thermochromic due to an additional lower energy emission band, which is absent at 77 K.     

Amphiphilic diblock,triblock, and star block copolymers by living radical polymerization: Synthesis and aggregation behavior

Copper(I)‐mediated living radical polymerization was used to synthesize amphiphilic block copolymers of poly(n‐butyl methacrylate) [P(n‐BMA)] and poly[(2‐dimethylamino)ethyl methacrylate] (PDMAEMA). Functionalized bromo P(n‐BMA) macroinitiators were prepared from monofunctional, difunctional, and trifunctional initiators: 2‐bromo‐2‐methylpropionic acid 4‐methoxyphenyl ester, 1,4‐(2′‐bromo‐2′‐methyl‐propionate)benzene, and 1,3,5‐(2′‐bromo‐2′‐methylpropionato)benzene. The living nature of the polymerizations involved was investigated in each case, leading to narrow‐polydispersity polymers for which the number‐average molecular weight increased fairly linearly with time with good first‐order kinetics in the monomer. These macroinitiators were subsequently used for the polymerization of (2‐dimethylamino)ethyl methacrylate to obtain well‐defined [P(n‐BMA)_x‐b‐PDMAEMA_y]_z diblock (15,900; polydispersity index = 1.60), triblock (23,200; polydispersity index = 1.24), and star block copolymers (50,700; polydispersity index = 1.46). Amphiphilic block copolymers contained between 60 and 80 mol % hydrophilic PDMAEMA blocks to solubilize them in water. The polymers were quaternized with methyl iodide to render them even more hydrophilic. The aggregation behavior of these copolymers was investigated with fluorescence spectroscopy and dynamic light scattering. For blocks of similar comonomer compositions, the apparent critical aggregation concentration (cac = 3.22–7.13 × 10^?3 g L^?1) and the aggregate size (ca. 65 nm) were both dependent on the copolymer architecture. However, for the same copolymer structure, increasing the hydrophilic PDMAEMA block length had little effect on the cac but resulted in a change in the aggregate size. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 439–450, 2002; DOI 10.1002/pola.10122