High glass transitions of novel organosoluble polyamide-imides based on noncoplanar and rigid diimide-dicarboxylic acid

Pilot Scale Hybrid Organic/Inorganic Coatings on a Polyolefin Separator to Enhance Dimensional Stability for Thermally Stable Long-Life Rechargeable Batteries

The electric vehicle and energy storage markets have grown rapidly in recent years. Thermal runaway caused by malfunctioning Li-ion batteries is an urgent issue with many causes (e.g., mechanical, electrical, and thermal abuse). The most common cause of thermal runaway is the formation of an internal short circuit because of damage to the separator. There has been significant effort to improve the design of separators, but to our knowledge, only inorganic nanoparticle coatings are used in commercial Li-ion batteries. Here, hybrid organic/inorganic coating layers are synthesized in a pilot-scale process that was developed from a crosslinkable polyamide-imide synthesis technique. The fabrication process is optimized to achieve reproducible hybrid organic/inorganic coating layers that are thin (≤4 μm), permeable (≤250 s/100 cc), and thermally stable beyond 150 °C. The hybrid coating layer is applied to mini-18650 Li-ion cells to show that the discharge capacity did not change at low discharge rates, and the retention capacity after 500 cycles was better than that of the reference cells used for comparison. This work demonstrates that a novel hybrid coating layer has the potential to improve the stability of commercial Li-ion batteries.

A Highly Hydrophilic and Biodegradable Novel Poly(amide-imide) for Biomedical Applications

A novel biodegradable poly(amide-imide) (PAI) with good hydrophilicity was synthesized by incorporation of l-glycine into the polymer chain. For comparison purposes, a pure PAI containing no l-glycine was also synthesized with a three-step method. In this study, we evaluated the novel PAI's thermal stability, hydrophilicity, solubility, biodegradability and ability to support bone marrow mesenchymal stem cell (BMSC) adhesion and growth by comparing with the pure PAI. The hydrophilic tests demonstrated that the novel PAI has possible hydrophilicity at a 38° water contact angle on the molecule surface and is about two times more hydrophilic than the pure PAI. Due to an extra unit of l-glycine in the novel PAI, the average degradation rate was about 2.4 times greater than that of the pure PAI. The preliminary biocompatibility studies revealed that all the PAIs are cell compatible, but the pure PAI exhibited much lower cell adhesion than the l-glycine-incorporated novel PAI. The hydrophilic surface of the novel PAI was more suitable for cell adhesion, suggesting that the surface hydrophilicity plays an important role in enhancing cell adhesion and growth.

Structure-Property Relationships of Soluble Poly(ester-urea)s containing Naphthyl Groups

The preparation of new types of polyureas with good thermal properties and improved solubility was investigated. Two new bulky diamines as new monomers for the preparation of polyurea were synthesized via two steps. First, a nucleophilic reaction of 1-naphthol and 2-naphthol with 3,5-dinitrobenzoyl chloride and then the reduction of the nitro groups by hydrazine hydrate/Pd-C to produce the corresponding diamines (1NA and 2NA). The poly(ester-urea)s were synthesized through the polyaddition reaction of the diamines with various commercially available diisocyanates. The polymers were characterized using IR and 1H NMR spectroscopy, elemental analysis, viscometry, thermal analysis, gel permeation chromatography (GPC), and X-ray diffraction. The copolymers were amorphous and readily soluble in a wide range of organic solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, N, N-dimethylformamide, and m-cresol. Thermal analysis showed a glass transition temperature between 146 and 178 °C. Their decomposition temperatures were more than 180 °C, and their 10% weight losses were in the range 281—315 ° C in air. The weight average molecular weights ( Mw) of the polymers were about 32 200—40 500 g/mol.

Development of one-step synthesized LDH reinforced multifunctional poly(amide–imide) matrix containing xanthene rings: study on thermal stability and flame retardancy

New exfoliated poly(amide–imide)/Zn–Al layered double hydroxide (LDH) nanocomposites were synthesized by solution intercalation using synthesized organo-modified LDH (OLDH) as nanofiller obtained by one-step method.

Processing of Thermally Stable Polymer Nanocomposites Reinforced Silicate Nanoparticles Based on N-trimellitylimido-L-phenyl alanine

In this article two polymer/nanocomposite films with 5 and 10% silicate particles based on Poly(amide-imide) (PAI) from N-trimellitylimido-L-phenyl alanine were prepared via solution intercalation method through blending of organoclay with the PAI solution. Poly(amide-imide) was synthesized by the direct polycondensation reaction of N-trimellitylimido-L-phenyl alanine with 4,4′-diamino diphenyl ether in the presence of triphenyl phosphite (TPP), CaCl2 and pyridine (Py). Morphology and structure of the resulting PAI-nanocomposite films were characterized by FTIR spectroscopy, X-ray diffraction and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using Uv-vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements.

New organosoluble aromatic poly(esterimide)s containing pendent pentadecyl chains

A new diimide dicarboxylic acid, namely 2,2′-(4-pentadecyl-1,3-phenylene)bis(1,3-dioxoisoindoline-5-carboxylic acid), containing preformed imide rings and pentadecyl chain, was synthesized by the reaction of 4-pentadecylbenzene-1,3-diamine with trimellitic anhydride. A series of new aromatic poly(esterimide)s (PEIs) was synthesized using diphenylchlorophosphate-activated direct polycondensation of 2,2′-(4-pentadecyl-1,3-phenylene)bis(1,3-dioxoisoindoline-5-carboxylic acid), with five commercially available bisphenols, namely 4,4′-isopropylidenediphenol (I), 4,4′-(hexafluoroisopropylidene)diphenol (II), 4,4′-oxydiphenol (III), 4,4′-biphenol (IV), and 4,4′-(9-fluorenylidene)diphenol (V) in the presence of pyridine and lithium chloride. Inherent viscosities of PEIs were in the range 0.54–0.83 dL g−1 in chloroform (CHCl3) at 30 ± 0.1°C. PEIs containing pendent pentadecyl chains were soluble in organic solvents such as CHCl3, m-cresol, N, N-dimethylacetamide, 1-methyl-2-pyrrolidinone, pyridine, and nitrobenzene. Tough, transparent, and flexible films of PEIs could be cast from their CHCl3 solutions. PEIs exhibited glass transition temperature in the range 145–198°C. The temperature at 10% weight loss of PEIs, determined by thermogravimetric analysis under the nitrogen atmosphere, was in the range of 450–470°C indicating good thermal stability.

Preparation and Characterization of Silica/Polyamide-imide Nanocomposite Thin Films

The functional silica/polyamide-imide composite films were prepared via simple ultrasonic blending, after the silica nanoparticles were modified by cationic surfactant-cetyltrimethyl ammonium bromide (CTAB). The composite films were characterized by scanning electron microscope (SEM), thermo gravimetric analysis (TGA) and thermomechanical analysis (TMA). CTAB-modified silica nanoparticles were well dispersed in the polyamide-imide matrix, and the amount of silica nanoparticles to PAI was investigated to be from 2 to 10 wt%. Especially, the coefficients of thermal expansion (CET) continuously decreased with the amount of silica particles increasing. The high thermal stability and low coefficient of thermal expansion showed that the nanocomposite films can be widely used in the enamel wire industry.