High-pressure synthesis of aliphatic polypyromellitimides via nylon-salt-type monomers composed of aliphatic diamines and pyromellitic acid diesters

Pellisier

et al. 2019

Recently, we have studied polyimides (PIs) synthesized by incorporating an aromatic diamine monomer with a methylene linker, 4,4 0 -methylenebis(2,6-dimethylaniline), to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to reduce rigidity. In this report, we incorporate a urea linkage into these materials in order to observe the effect of additional hydrogen bonding. The polymers are designed to exhibit thermal properties in between those of conventional aromatic PIs and polymers with wholly aliphatic ether diamine links. Herein, we demonstrate that the addition of 1,6 hexamethylene diisocyanate and the increase of hydrogen bonds at the urea linkage can be used to improve the thermal and mechanical properties of the PI. Furthermore, the imide ring is an important component to maintain the thermal stability characteristics in polyimidepolyurea hybrids. The polymers were characterized by FTIR, thermomechanical and calorimetric analysis, microhardness, and tensile testing.

Section: Introductionmentioning

confidence: 99%

Thermomechanical characterization of thermoplastic polyimide–polyurea to improve the chain interaction via internal hydrogen bonds

Pellisier

et al. 2019

“…These monomers are more specialized and more expensive than most polymer materials. A variety of synthetic methods are used to manufacture these polymeric materials with tunable properties.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical characterization of thermoplastic polyimides to improve the chain collaboration via ureidopyrimidone endcaps

Pellisier

et al. 2019

In this report, we explored the effect of incorporating ureidopyrimidone (UPy) linkers in a series of polyimides (PIs) previously studied in our laboratory. The polymers consist of an aromatic diamine monomer with a methylene linker, 4,4′’‐methylenebis (2,6‐dimethylaniline), used to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to decrease rigidity. The polymers were designed to exhibit thermal properties in between those of conventional aromatic PIs and polymers with wholly aliphatic ether diamine links, with an aim to improve the mechanical characteristics. Through dynamic mechanical analysis and differential scanning calorimetry, it is shown that the UPy linkers with their four‐hydrogen bond sites are introduced to connect the chains in series. The connection strengthens the chain interactions and increases the range of the thermal and mechanical properties of the PI. Furthermore, the connecting regions are an important component to preserve the thermal stability of PIs while maintaining the processability. The polymers were characterized by FTIR, nuclear magnetic resonance, GPC, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, microhardness, and tensile testing. POLYM. ENG. SCI., 59:2231–2246, 2019. © 2019 Society of Plastics Engineers

“…These characteristics make them a sustainable option in the production of high performance products found in electronics, aerospace structural components, thermal insulation, composites, and adhesives . The sizeable number of monomer combinations and the different synthetic methods allow for their properties to be tailored depending on the suitable application, but it comes at a monetary cost compared to other polymer classes. Hence, the chemistry of polyimides is rather diverse with a variety of usable monomers and several methodologies available for synthesis.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical characterization of thermoplastic polyimide to improve the chain interaction via crystalline domains

Craft

et al. 2019

In a previous study on polyimides, we incorporated an aromatic diamine monomer with a methylene linker, 4,4 0 -methylenebis (2,6-dimethylaniline), to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to decrease rigidity. In this report, we explore the behavior of crystalline regions provided by the organized packing of polyethylene oxide into the formerly characterized polymers. The polymers were designed to exhibit thermal properties in between those of conventional aromatic polyimides and polymers with wholly aliphatic ether diamine links, with a target to improve the mechanical characteristics. Through dynamic mechanical analysis and differential scanning calorimetry, it is shown that the incorporation of polyethylene oxide diamine and the removal of methyl pending groups serve to improve the organized packing of the chains. All of this allows for a broader range in tenability of thermal and mechanical properties of the polyimide. Furthermore, the crystalline regions are an important component to maintain the temperature stability of polyimide while maintaining the processability. The polymers are characterized by Fouriertransform infrared spectroscopy, thermomechanical and calorimetric analysis, microhardness measurements, tensile testing, and wide-angle X-ray scattering.