5-sulfoisophthalate Sodium Research Articles

Highly selective detection of Fe3+ and nitro explosives by a bifunctional sensor based on Cd(II) complex

A cadmium fluorescence framework [Cd(sip)(dpa)(H2O)] n (1) (NaH2sip = sodium 5-sulfoisophthalate; dpa = 4,4’-dipyridylamine) has been successfully synthesized and characterized. Single crystal X-ray diffraction analysis reveals that complex 1 exhibits an infinite 1D double chain, the H-bonds extend the 1D chains into a 3D supermolecular framework. Fluorescent studies reveal that 1 can be used as a highly sensitive luminescent sensor for detecting Fe3+ ion in H2O and 4-nitrophenol (4-NP) in DMF within a few seconds through fluorescence quenching. The sensing mechanism for Fe3+ can be explained in terms of synergistic competitive absorption and coordination interactions between Fe3+ and the framework, while the mechanism for detecting 4-NP is mainly attributed to the competitive absorption between the excitation/emission of 1 and analytes.

Effect of synthesized sulfonate derivatives as nucleating agents on crystallization behavior of poly(lactic acid)

ABSTRACT The improvement of the crystallization of poly(lactic acid) (PLA) is one of the key areas to allow PLA to perform better at higher temperature and load bearing. Due to its slow crystallization rate, either organic or inorganic nucleating agents (NAs) can be used to improve the crystallization rate of PLA. In the case of organic NAs, aromatic sulfonate salt and bisamide compounds are promising ones because they can control better clarity. The aim of this work was to study the crystallization behavior of PLA using as-synthesized dimethyl 5-sulfoisophthalate sodium salt (SSIPA) as a nucleating agent in comparison with the commercial sulfonate salt (LAK-301). Two grades of PLA (PLA L105 and PLA 3251D) were used in this study. PLA samples were prepared by internal mixer and compression molding. All samples were investigated by DSC and POM. The results from DSC showed that after introducing the nucleating agents into PLA, the crystallinity in all samples was improved. The highest crystallinity at 57.48% was obtained from PLA L105/SSIPA1.0. Isothermal crystallization kinetics showed the improvement in overall crystallization rate of PLA with nucleating agents. The lowest half time crystallization obtained was 1.19 min for PLA L105/SSIPA1.0 at 135 °C. The results from POM indicated the substantial increase of the nucleus density and smaller spherulite size upon adding nucleating agents.

Two Transition Metal Coordination Polymers: Luminescent Sensing Properties and Treatment Effect on Chronic Periodontitis by Reducing IL-6 and TNF-α Content.

Two novel sulfonic functionalized coordination polymers (CPs) {[Cd1.5(dimb)(5-sip)(H2O)3]·3H2O}n (1, dimb = 1,4-di(1H-imidazol-1-yl)butane) and [Co2(iptz)(Hiptz)(5-sip)(H2O)]·4H2O (2, Hiptz = 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole) were acquired via different metal(II) salts reacting with the mixed ligands containing 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole, 1,4-di(1H-imidazol-1-yl)butane and sodium 5-sulfoisophthalate (NaH2sip), respectively. Furthermore, the complex 1 based on Cd(II) could be utilized as the luminescent senor for picric acid (PA) detection in water. In bio-research, compounds 1 and 2 treatment effect on chronic periodontitis was assessed and the specific mechanism was discussed. First of all, the RT-PCR was performed to measure the HmuY and fimA genes relative expression level in P.gingivalis after treated by compounds 1 and 2. Then, the TNF-α and IL-6 content in the fluid of gingival crevicular after compounds treatment was determined with ELISA detection kit.

The syntheses, structures, and properties of metal-organic frameworks based on mixed multi-N donor and carboxylate ligands

Four new metal-organic frameworks [Zn3(HL)2(btc)2(H2O)2]·H2O (1), [Mn(H2L)(btc)(H2O)] (2), [Zn2(L)(HL)(SIP)(H2O)]·4H2O (3) and [Cd(H2L)(SIP)(H2O)]·3H2O (4) were obtained by reactions of the different metal(II) salts with mixed ligands including 1,2,3-benzenetricarboxylic acid (H3btc), sodium 5-sulfoisophthalate (NaH2SIP) and 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole (HL), respectively. All compounds were characterized by single-crystal X-ray diffraction, FT-IR spectroscopy, and elemental analysis. The study shows that the natures of organic ligands as well as metal ions play key roles in modulating the resulting frameworks of 1–4. The complex 1 is a (3, 4, 4)-connected three-dimensional (3D) net with the point (Schläfli) symbol of (42·63·8)4(64·8·10), while 2 is a two-dimensional (2D) layer structure referred as fes net with a Point (Schläfli) symbol of (4·82). Complex 3 has 2-nodal (3, 3, 4)-connected rare tfc net with a Point (Schlafli) symbol of (83)2(85·10), while 4 is a supramolecular polymer constructed from infinite one-dimensional (1D) chains by the interaction of rich hydrogen bonds and π - π stacking. The luminescent properties have been investigated for the compounds 1, 3, and 4 containing metal d10 Zn(II) and Cd(II) atoms.

Four new transition metal coordination polymers based on mixed 4-imidazole and carboxylate–sulfonate ligands: Syntheses, structures, and properties

Four new metal-organic coordination polymers [Zn(HL)(SIP)(H2O)]·2H2O (1), [Cd2(L)(H2L)(SIP)2] (2), [Cu2(L)2(SIP)(OH)]·2H2O (3) and [Ni3(L)4(SIP)2(H2O)4]·6.5H2O (4) were obtained by reactions of the different metal(II) salts with mixed ligands including sodium 5-sulfoisophthalate (Na3SIP) and 1,4-di(1H-imidazole-4-yl)benzene (L), respectively. All compounds were characterized by FT-IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The study indicates that different natures of metal ions play crucial roles in modulating the formation of the resulting frameworks. Compound 1 is a one-dimensional (1D) chain structure, and 2 is a (3, 8)-connected tfz-d three-dimensional (3D) net with a Point (Schlafli) symbol of (43)2(46·618·84). Complex 3 has (3, 5)-connecting node two-dimensional (2D) network with a Point (Schlafli) symbol of (42·67·8)(42·6) based on the {Cd2(OH)(SO3)}n2+ binuclear Cd(II) motif, while 4 is a rare 2D ​+ ​2D → 3D polycatenated framework resulting from two different kinds of (4, 4) 2D layers. The photoluminiscent properties as well as quantum yield (QY) and luminescence lifetime are also investigated for compounds 1 and 2 in the solid state.

Auxiliary dipyridylamide ligand control of dimensionality in copper 5-sulfoisophthalate coordination polymers

Abstract Hydrothermal reaction of copper nitrate, sodium 5-sulfoisophthalate (sip), and a long-spanning hydrogen-bonding capable dipyridylamide ligand afforded four coordination polymers whose dimensionality depends critically on the dipyridylamide tether length. The four new phases were structurally characterized via single-crystal X-ray diffraction. {[Cu 8 (sip) 4 (pbn) 3 (nic)(μ 3 -OH) 2 (μ 2 -OH)(μ 2 -H 2 O)(H 2 O) 4 ]·5H 2 O} n ( 1 , pbn = 1,3-propanediaminebis(nicotinamide), nic = nicotinate) manifests an intriguing 2D slab structure featuring trimeric copper clusters containing bridging hydroxide ions and water molecules along with substantial crystallographic disorder. {[Cu 3 (sip) 2 (pbin) 4 (H 2 O) 4 ]·14H 2 O} n ( 2 , pbin = 1,3-propanediaminebis(isonicotinamide)) shows 1D chain motifs with curled conformation dipyridylamide ligands. {[Cu 4 (μ 3 -OH) 2 (sip) 2 (hbin)]·2H 2 O} n ( 3 , hbin = 1,6-hexanediaminebis(isonicotinamide)) features [Cu 4 (μ-OH) 2 (sip) 2 ] butterfly clusters connected into a 3D 3,8-connected network with (4.6 2 ) 2 (4 2 6 18 7 4 8 4 ) topology. {[Cu(Hsip)(hbn)(H 2 O)]·2H 2 O} n ( 4 , hbn = 1,6-hexanediaminebis(nicotinamide)) exhibits a sawtooth (4,4) grid topology. Variable temperature magnetic susceptibility studies on 1 and 3 revealed antiferromagnetic behavior ( g = 2.079(6), J = −5.7(2) cm −1 for 1 , g = 2.14(2), J 1 = −19(1) cm −1 , J 2 = −35(2) cm −1 for 3 ). Thermal decomposition behavior of 1 – 4 is also discussed.

Structural elucidation, EPR and magnetic property of a Co(III) complex salt incorporating 4,4′-bipyridine and 5-sulfoisophthalate

The cobalt(III) derivative [Co3(sip)4(bipy)2(H2O)10][Co(bipy)2(H2O)4]3(sip)2·20H2O (1) has been hydro(solvo) thermally synthesized by combining sodium 5-sulfoisophthalate (sipH2Na) as organic linker, divalent cobalt nitrate hexahydrate as metal salt and the flexible N-donor ancillary ligand bipy (4,4′-bipyridine). Compound 1 is an ionic solid consisting of both cobalt containing cations and anions and also in addition 5-sulfoisophthalate anions. Cobalt containing cations in the crystal structure are mononuclear complex while cobalt containing anion is a discrete trinuclear species. The π–π interaction present in 1 results in chain supramolecular structure. The encapsulation of the cobalt compound displays a moderate luminescent property. On temperature dependent magnetic study, it is revealed that the corresponding effective magnetic moment is 5.27 B.M. at 300 K, which suggests isolated Co(III) species with S = 2 (theoretical value is 4.90 B M.) and thus 1 shows a rare paramagnetic behavior.

Alkaline hydrolysis and pretreatment of trilobal high dimethyl 5-sulfoisophthalate sodium cationic dyeable polyester

Lower glass transition temperature and crystallinity degree of trilobal high dimethyl 5-sulfoisophthalate sodium cationic dyeable polyester (THCDP) led to its more sensitivity to strong alkali and high temperature than regular Poly(ethylene terephthalate) (PET). The kinetic behaviors of alkaline hydrolysis of THCDP and PET were further explored, and the kinetics equations determined by regression analysis manifested that THCDP with high content of dimethyl 5-sulfoisophthalate sodium salt (SIP) was more prone to alkali hydrolysis and had higher weight loss rate. A comparatively lower power consumption pretreatment process of THCDP knitted fabrics benefited from the synergistic effect of various additives was applied in this study by response surface methodology and the optimum process with less auxiliaries, especially with less caustic treatment avoided large strength loss of fabric, as well as lower manufacturing cost in an environmentally friendly way.

Cationic dyeing properties of trilobal high dimethyl 5-sulfoisophthalate sodium salt (SIP) content cationic dyeable polyester (THCDP) fabrics

To make the polyester ionically dyeable, trilobal high dimethyl 5-sulfoisophthalate sodium salt (SIP) content cationic dyeable polyester (THCDP) was developed in this study which aimed to investigate its structural and dyeing properties. Its lower glass transition temperature and crystallinity degree contributed to lower dyeing temperature. A low-cost and environmentally friendly dyeing solution was applied in this study and the dyeing temperature of newly THCDP fabric could be reduced to 90°C, distinctly different from the previous cationic dyeable polyester which needed more than 100°C to reach dyeing standard. Meanwhile, THCDP showed its higher dyeing saturation value than normal acrylic fabric and cationic dyeable polyester with the Cationic Red X-GRL dyestuff. In present, both pure THCDP and blend textiles were developed. A series of THCDP/Cotton blends’ (20/80, 35/65, 65/35, 80/20) dyeing behaviors were tested, and found they could be dyed at 90°C with good color fastness and levelness.

Zero-, one- and two-dimensional bis-triazole-bis-amide-based copper(II) complexes tuned by polycarboxylates with different protonation degrees: assembly, structures and properties

Three bis-triazole-bis-amide-based copper(II) complexes with different dimensionality, [Cu(dtcd)2 (1,3-HBDC)2]·2H2O (1), [Cu(dtcd) (1,3,5-H2BTC)2]·2H2O (2) and [Cu4(μ3-OH)2(dtcd)2(SIP)2]·4H2O (3) (dtcd = N,N′-di(4H-1,2,4-triazole) cyclohexane-1,4-dicarboxamide, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid, NaH2SIP = sodium 5-sulfoisophthalate), have been synthesized under different pH values and structurally characterized. Complex 1 exhibits a zero-dimensional mononuclear structure with one carboxyl group of 1,3-HBDC coordinating to copper(II), while the other carboxyl group is protonated. In complex 2, the CuII ions are bridged by the dtcd ligands forming a one-dimensional chain, in which only one carboxyl group of 1,3,5-H2BTC coordinates with the metal, while the others are protonated. Complex 3 possesses a two-dimensional network based on tetranuclear Cu4 clusters supported by the dtcd and nonprotonated SIP ligands. The various structures clearly indicate that the pH and polycarboxylates have a great influence on the dimensionality and structures of 1–3. The luminescence properties of 1–3 and magnetic properties of 3 were investigated.

Synthesis and characterization of a water-soluble nylon copolyamide

A novel water-soluble copolyamide based on Nylon 66 was synthesized via solution-melt polycondensation of hexanedioic acid and sodium 5-sulfoisophthalate with 1,6-diaminohexane. The chemical structures of the products were ascertained by various spectroscopic techniques (FT-IR, Raman, and 1H NMR). The thermal properties of the polyamides under consideration were measured by TGA and DSC. According to the temperature dependence of FTIR spectra, it was found that the average strength of the intermolecular hydrogen bond of the water-soluble copolyamides becomes weak with increasing the temperature. It was found that the obtained random copolyamides could self-assemble into spherical micelles in aqueous solution with the size dependent on the hydrophilic fraction according to the DLS and TEM measurements.

Synthesis and characteristics of UV curable dimethyl 5-sulfoisophthalate sodium salt-co-diethylene glycol with maleic and phthalic anhydride copolymers (DMSIP-co-DEG-co-MA/PA) for application in redox flow batteries

Dimethyl 5-sulfoisophthalate sodium salt (DMSIP)-co-diethylene glycol (DEG)-co-maleic anhydride (MA)/phthalic anhydride (PA) oligomers were synthesized via condensation reaction and the corresponding membranes were prepared by UV curing. The number-average molecular weight (Mn) of the DMSIP-co-DEG-co-MA/PA (DDMP) was proportional to the concentration of DMSIP and ranged from 1,360–2,856 g/mol. A successful introduction of a -SO3Na group to the main oligomer chain was confirmed using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy and the thermal stability of the membranes up to 300 °C was analyzed using thermogravimetric analysis (TGA). The water uptake values, swelling ratios, and the ion-exchange capacities of the membranes were 13%–30%, 7%–15%, and 0.7–0.9 meq/g, respectively. The electrical properties of the membrane, including the area resistance, ion transport number, and the cyclic charge-discharge current were also analyzed; these properties confirmed that these membranes were suitable for use in redox flow battery (RFB) applications. Open image in new window

Synthesis and characteristics of a cross-linked DMSIP-co-HDO-co-MA ion-exchange membrane for redox flow battery applications

Novel ion-exchange membranes composed of dimethyl 5-sulfoisophthalate sodium salt (DMSIP), 1,6-hexanediol (HDO), isophthalic acid (IPA) and maleic anhydride (MA) were prepared by the synthesis of a DHIM oligomer and UV-cross-linking. The basic properties of the membranes were characterized, and a redox flow battery (RFB) test was conducted. The conversion and molecular weight of the DHIM oligomer decreased with increasing DMSIP contents; the maximum conversion and molecular weight values were 90.8% and 1335–1620g/mol, respectively. The thermal stability of the cross-linked DHIM ion-exchange membrane was 370°C. The water uptake and ion-exchange capacity increased as the DMSIP contents increased, and the maximum values were 43.1% and 1.23meq/g. The minimum values for the electrical resistance and ion transport were 0.27Ωcm2 and 0.998, respectively. Charge–discharge, voltage and energy efficiencies increased with the increasing extent of cross-linking, and their values were 90.81%, 79.92% and 71.52%, respectively. The minimum value of methanol permeability was lower than that of Nafion 117®, which indicates that the membrane has higher ion selectivity than Nafion 117®.

Three tetranuclear copper(II) cluster-based complexes constructed from 4-amino-1,2,4-triazole and different aromatic carboxylates: Assembly, structures, electrochemical and magnetic properties

Three new tetranuclear copper(II) cluster-based complexes constructed from 4-amino-1,2,4-triazole (atrz) and three types of aromatic carboxylates, [Cu4(μ3-OH)2(atrz)2(DNBA)6] (1), [Cu4(μ3-OH)2(atrz)2(1,3-BDC)3]·2H2O (2) and [Cu4(μ3-OH)2(atrz)2(SIP)2]·4H2O (3) (HDNBA=3,5-dinitrobenzoic acid, 1,3-H2BDC=1,3-benzenedicarboxylic acid and NaH2SIP=sodium 5-sulfoisophthalate), have been hydrothermally synthesized and structurally characterized. Complex 1 displays a single-molecular CuII4 cluster structure, which is further connected by the intermolecular hydrogen-bonding interactions to form a 2D supramolecular layer. In 2, there also exist tetranuclear CuII4 clusters, which are linked by the 1,3-BDC anions to give a 3D NaCl-type framework. In 3, the CuII4 clusters are connected by the carboxyl and sulfo groups of SIP anions to generate 3D (4,8)-connected framework with a (410·614·84)(45·6)2 topology. The atrz ligand conduces to the construction of tetranuclear copper(II) clusters and the carboxylates with different non-carboxyl substituent show important effects on the final structures of the title complexes. The electrochemical and magnetic properties of 1–3 have been investigated.

Crystal polymorphism of sodium benzene-1,3-dicarboxy-5-sulfonate monohydrate

Two different crystal forms of sodium 5-sulfoisophthalate monohydrate have been found and structurally characterized by X-ray diffraction and FT-IR spectroscopic methods. Polymorph I is monoclinic, P2 1/ n, and polymorph II is triclinic, P1. The analysis of the crystal structures reveals that the connectivity patterns in both polymorphs are different. Two of the sulfonate oxygen atoms (sites) interchange their function and are used to accept two hydrogen bonds in the first polymorph or to donate two bonds toward the metal ion in the second polymorph. Consequently the hydrogen-bonded anionic subnetwork reduces from two-dimensional in I to one-dimensional in II. The FT-IR spectra correlate well with the structural peculiarities of the crystals and reflect the variation of hydrogen-bonded networks in them.

Thermal properties and chemical changes in blend melt spinning of cellulose acetate butyrate and a novel cationic dyeable copolyester

AbstractA novel cationic dyeable copolyester (MCDP) containing purified terephthalate acid (PTA), ethylene glycol (EG), 2‐methyl‐1,3‐propanediol (MPD), and sodium‐5‐sulfo‐isophthalate (SIP) was synthesized via direct esterification method. The chemical structure of modified cationic dyeable polyester (MCPD) was confirmed by FTIR and 1H‐NMR. The thermal properties of MCDP and cellulose acetate butyrate (CAB) blends with different blend ratios were investigated by DSC. The results revealed that MCDP and CAB were immiscible polymer blends, and the glass transition temperature of CAB in blend fibers was higher than that of CAB in blend chips because of the strengthening hydrogen bonding. The chemical changes of MCDP and CAB in blend melt spinning were analyzed. It was found that the thermal hydrolysis reaction of ester side groups of CAB occurred in blend melt spinning, which resulted in that the acid gas was produced and the hydroxyl group content of CAB was increased. Furthermore, the moisture absorption of blend fibers was improved about three times than pure MCDP fiber even after washing 30 times. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis of poly(butylene terephtahlate) nanocomposites using anionic clays

The synthesis of poly(butylene terephthalate) (PBT) nanocomposites by in situ polymerisation method using an organo-modified layered doubled hydroxide is described. 4-Sulfobenzoic acid potassium salt, sodium dodecyl sulfate and dimethyl 5-sulfo isophthalate sodium salt were used as intercalating compounds to improve clay exfoliation. The thermal and dynamic mechanical properties of the nanocomposites prepared were investigated and compared to those of montmorillonite-type nanocomposites prepared by similar synthetic route. The nanocomposites obtained, independent of the degree of exfoliation, showed better dynamic mechanical properties respect to PBT homopolymer while improvements in thermal stability were achieved when dimethyl 5-sulfo isophthalate was used as intercalating agent, highlighting the importance of the interactions of ionic groups covalently linked to the polymer with the charged clay platelets.

Synthesis and Characterization of Poly(Ethylene Glycol)-Based Single-Ion Conductors

A series of ionomers was synthesized by melt polycondensation of poly(ethylene glycol) (PEG) oligomers and dimethyl 5-sulfoisophthalate sodium salt. The molar mass of the PEG spacer was either 400, 600, or 900, and the cation was exchanged from sodium to lithium or cesium by dialysis. Since the anions are covalently attached to the ionomer chains and are essentially immobile relative to the cations, these ionomers are excellent models for polymeric single-ion electrolytes. The experimental evidence to date suggests that the cations do not aggregate to form the usual ion clusters seen in other ionomers. No relaxation time associated with ion clusters was observed in rheological measurements, nor was an “ionomer peak” observed in small-angle X-ray scattering measurements. The ionic conductivity increases significantly with increasing PEG spacer molecular weight, although the total cation content decreases at the same time. At room temperature, the highest conductivity (10-6 S/cm) was achieved for the sodium...

Effect of compatibilization on the oxygen‐barrier properties of poly(ethylene terephthalate)/poly(m‐xylylene adipamide) blends

AbstractThe improvement of the oxygen‐barrier properties of poly(ethylene terephthalate) (PET) via blending with an aromatic polyamide [poly(m‐xylylene adipamide) (MXD6)] was studied. The compatibilization of the blends was attempted through the incorporation of small amounts of sodium 5‐sulfoisophthalate (SIPE) into the PET matrix. The possibility of a transamidation reaction between PET and MXD6 was eliminated by 13C‐NMR analysis of melt blends with 20 wt % MXD6. An examination of the blend morphology by atomic force microscopy revealed that SIPE effectively compatibilized the blends by reducing the MXD6 particle size. Thermal analysis showed that MXD6 had a nucleating effect on the crystallization of PET, whereas the crystallization of MXD6 was inhibited, especially in compatibilized blends. Blending 10 wt % MXD6 with PET had only a small effect on the oxygen permeability of the unoriented blend when it was measured at 43% relative humidity, as predicted by the Maxwell model. However, biaxially oriented films with 10 wt % MXD6 had significantly reduced oxygen permeability in comparison with PET. The permeability at 43% relative humidity was reduced by a factor of 3 in compatibilized blends. Biaxial orientation transformed spherical MXD6 domains into platelets oriented in the plane of the film. An enhanced barrier arose from the increased tortuosity of the diffusion pathway due to the high aspect ratio of MXD6 platelets. The aspect ratio was calculated from the macroscopic draw ratio and confirmed by atomic force microscopy. The reduction in permeability was satisfactorily described by the Nielsen model. The decrease in the oxygen permeability of biaxially oriented films was also achieved in bottle walls blown from blends of PET with MXD6. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1361–1370, 2005

Improving gas barrier of PET by blending with aromatic polyamides

Improvement of gas-barrier properties of poly(ethylene terephthalate) (PET) by blending with an aromatic polyamide, either poly( m-xylylene adipamide) (MXD6) or a copolyamide based on MXD6 in which 12 mol% adipamide was replaced with isophthalamide (MXD6-12I), was studied. Incorporating a small amount of sodium 5-sulfoisophthalate into the PET matrix compatibilized the blends and reduced the polyamide domain size to 100–300 nm. Thermal analysis showed that the polyamides had a nucleating effect on PET crystallization, whereas crystallization of the polyamides was inhibited especially in compatibilized blends. Without orientation, blending with 10 wt% MXD6 or MXD6-12I reduced oxygen permeability of PET by a factor of about 0.8 ( P/ P PET) when measured at 43% relative humidity (RH), in accordance with the Maxwell model prediction. However, after biaxial orientation, oxygen permeability of blends with 10 wt% MXD6 was reduced by 0.3 at 43% RH, and permeability of blends with 10 wt% MXD6-12I was reduced by 0.4. Even at 85% RH, oxygen permeability was reduced by 0.4 and 0.6 for blends with MXD6 and MXD6-12I, respectively. Blending with an aromatic polyamide was even more effective in reducing carbon dioxide permeability of oriented PET. Transformation of spherical polyamide domains into platelets of high aspect ratio increased tortuosity of the diffusion pathway. The platelet aspect ratio predicted by the Nielsen model was confirmed by atomic force microscopy. Higher aspect ratio of MXD6 domains was ascribed to a lower T g compared to MXD6-12I. Similar reduction in oxygen permeability was achieved in bottle walls blown from PET blends with MXD6 or MXD6-12I.