A new Trö ger's base-containing aromatic dihydrazide, 2,8-bis(carboxylic)-6H, 12H-5,11-methanodibenzo-[b,f] [1,5]-diazocine dihydrazide, was prepared by the condensation of ethyl p-aminobenzoate with hexamethylenetetramine in the presence of trifluoroacetic acid, followed by converting to the dihydrazide with a high yield and high purity. A series of novel aromatic polyhydrazides were prepared from the Trö ger's unit containing dihydrazide and various aromatic diacyl chlorides via low-temperature solution polycondensation in quantitative yields. All the polyhydrazides were amorphous and readily soluble at room temperature in polar organic solvents such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with good glass transition temperatures (163-172 C), 10% weight-loss temperatures in excess of 460 C, and char yields at 800 C in nitrogen higher than 39%.

Background: Recapitulating the native cell niche and extracellular matrix (ECM) architecture in vitro helps reconstruct injured tissues. Collagen I and heparin are two important constituents of the ECMs, which play crucial roles in regulating cell behaviors. Specifically in the liver, these components can affect the differentiation and functionality of the cells.

In this paper, a new high molecular weight 4-arm star polymethylmethacrylates (PMMA) is synthesized by a "core-first" method. The process is as follows: tetra-functional initiator is synthesized by esterification reaction of ethylenediamine-N,N,N',N'-tetra-2-propanol. The reaction creates a new core that is used as an initiator and employed in the homogenous atom transfer radical polymerization (ATRP) of MMA monomer. The ATRP process is carried out in presence of CuBr as a catalyst and 2,2'-bipyridine ligands to synthesize star polymers with high conversion, low polydispersity and nearly monomodal molecular distributions.