Pentaerythritol (PE), pyromellitic dianhydride
(PDA), and 1,1,1 tris(hydroxyl methyl)propane (TMP) were purchased from Sigma Aldrich, India.
Construction of polymeric methylene diphenyl diisocyanate (PMD) and Pyromellitic dianhydride
(PMDA) production facilities.
2 mol) to a stirred solution of pyromellitic dianhydride
The [epsilon]' values were comparable with that of H polyimide film--a polyimide based on pyromellitic dianhydride
and 4,4'-diaminodiphenylether, which is one of the most common high-performance dielectrics used in microelectronic applications, having a dielectric constant of 3.
The success of pyromellitic dianhydride
(PMDA) and 3,3,4,4' benzophenonetetracarboxylic dia-nhydride (BTDA) as epoxy hardening agents is attributed to their tetrafunctionality, which leads to higher density of crosslinks, thus higher heat distortion temperature (HDT) and increased chemical and solvent resistance (17).
PAA a condensation product of benzene-1, 2, 4, 5-tetra-carboxylic-l,2, 4, 5-dianhydride or pyromellitic dianhydride
(PMDA), and 4, 4'-diaminodiphenyl ether or oxydianilline (ODA) was procured from M/s ABR Organics, Hyderabad, India and this product was marketed as ABRON S-10.
polyamic acid (PAA) having molecular weight 42,000 a condensation product of pyromellitic dianhydride
and oxydianiline (ODA).
20, 21] mentioned molar complexes between the studied solvent, 1-methyl-2-pyrrolidinone (NMP) and pyromellitic dianhydride
dianiline poly(amic acid)s where four molecules of NMP hydrogen bond to the repeat unit of the precursor creating populations of bound and free species of NMP.
16] using pyromellitic dianhydride
(PMDA) as a tetrafunctional chain extender.
We have reported two new [pi]-conjugated diamines, 5,5'-bis(4-arninophenyl)-2,2'-bifuryl (PFDA) and 2,2'-bis(furyl)benzidine (FurylBZ), and their polyimides (PIs), prepared from pyromellitic dianhydride
(PMDA) (14, 15).
Polyanhydrides, particularly pyromellitic dianhydride
(PMDA) (24, 25), and polyepoxides (26-28) have been widely used for chain extension and branching of PET, allowing a significant increase in molecular weight, intrinsic viscosity, and melt viscosity.
(PMDA) and benzidine (BZD) are also commercially available, and were used as received.