Ji et al., "Synthesis and thermal behaviors of 1,3-bis(4-aminophenoxy)benzene (TPER) and polyimide based on TPER and pyromellitic dianhydride
," Journal of Thermal Analysis and Calorimetry, vol.
Pentaerythritol (PE), pyromellitic dianhydride
(PDA), and 1,1,1 tris(hydroxyl methyl)propane (TMP) were purchased from Sigma Aldrich, India.
Adding a solution dropwise of 4bromoaniline (24.40 g, 0.2 mol) to a stirred solution of pyromellitic dianhydride
(21.813 g, 0.1 mol) and keeping the temperature of the medium close to 40-50[degrees]C for an hour (Scheme 1), thus obtained ensuing solution was poured into ice water in which the reaction product precipitated.
In this work, we synthesized polyimides by incorporating an aromatic diamine monomer with a methylene linker, 4,4'-methylenebis(2,6-dimethylaniline) (MBDMA), along with aliphatic polyetherdiamine backbone linkers and pyromellitic dianhydride
(PMDA) as seen in Fig.
The reactive extrusion with pyromellitic dianhydride
(PMDA) and epoxy-based tetraglycidyl diamino diphenyl methane (TGDDM) results in a fundamentally different rheological behavior, which can be related to the initial molar mass, the synthesis route of the virgin PET grades and the reactivity of the chain extender employed.
In 1955, high molecular weight aromatic polyimides were synthesized by a two-stage polycondensation of pyromellitic dianhydride
(PMDA) with diamines [1, 2], This class of polymers has been growing steadily because of their thermo-oxidative stability, unique electrical properties, high radiation and solvent resistance, and high mechanical strength.
Although some common and cheap monomers such as pyromellitic dianhydride
(PMDA) and 4,4'-diaminodiphenyl ether (ODA) can be used for the synthesis of polyimide, it is still difficult to obtain high-performance membranes in hollow fiber configuration.
used pyromellitic dianhydride
(PMDA) in combination with triglycidyl isocyanurate (TGIC) and 1,4-phenylene-bis-oxazoline (PBOZ) to achieve long chain branched structures.
For instance, Park and Farris  had prepared the pyromellitic dianhydride
(PMDA)/oxidianiline (ODA) fibers with the tensile strength and initial modulus of 0.4 GPa and 5.2 GPa, respectively.
And pyromellitic dianhydride
(PMDA) has been frequently used as PET modifier.
Two kinds of modified PET, namely, n-m-PET and mm-PET, were synthesized through an in situ polymerization-modification process using pentaerythritol (PENTA) and pyromellitic dianhydride
(PMDA) as modifying monomers, respectively.