The relationship between solubility and nucleating effect of organic nucleating agent in poly(L‐lactic acid)

Abstract

N,N 0 -bis(benzoyl) hexanedioic acid dihydrazide (BHAD), and N,N 0 -bis(benzoyl) terephthalic acid dihydrazide (BTAD) were synthesized as the organic nucleating agents for poly(L-lactic acid) (PLLA). These two organic compounds exhibited different nucleating effect to PLLA. When the concentration was very low, BTAD was able to nucleate PLLA, while BHAD was not. When the concentration was adequate, BHAD showed better nucleating effect than BTAD. The experiments showed that, BHAD had the ability of dissolving into PLLA melt matrix, while BTAD was insoluble in PLLA. The optical microscope images revealed the quite different PLLA crystal morphologies nucleated by BHAD and BTAD. As BTAD could not dissolve in PLLA melt, it only induced a mass of small grain crystals of PLLA, the morphology of which is the same as neat PLLA. BHAD had relatively different nucleation and crystallization behaviors. Upon heating, BHAD could partially or totally dissolve in PLLA melt, which depended on the final heating temperature and its concentration. Upon cooling, BHAD separated from PLLA matrix and formed needle like or dendritic structures. Moreover, totally dissolved BHAD could finally exhibit dendritic structures, which had an excellent nucleation effect to PLLA.

Thermal performances and optical property of poly(L-lactic acid) under the influence of N,N'-dodecanedioic bis(3-phenylpropionic acid) dihydrazide as a crys­tal­lization promoter

“…Upon to now, many compounds with inorganic structures, organic structures, or inorganic/organic hybrid structures had been employed to investigate their nucleation effect on the crystallization process of PLLA. And the current typical nucleating agents include talc [12,13], montmorillonite [14,15], silicon dioxide [16], calcium carbonate [17,18], phenylphosphonate metals [19,20], metallic phenylmalonate salts [21], 1H-benzotriazole derivatives [22,23], benzoyl hydrazine derivatives [24,25], etc. For examples, upon the addition of 0.5 wt % commercial graphene oxide nanoplatelets, the half-time of crystallization of the PLA stereocomplex lower to around 5.5 min at 165°C [26].…”

The Nucleated Poly(L-lactic acid): The Role of a Phenylacetic Hydrazide Derivative

“…Organic small molecule nucleating agents, in comparison to inorganic nucleating agents or organic macromolecular nucleating agents, possess a remarkable advantage of flexible molecular structure construction, and some common structures like amide, benzene and alkyl chain are concluded as basic structures for promoting PLLA's crystallization. Thus many new organic compounds were synthesized to serve as a nucleating agent, or some existing commercial organic small molecule compounds were selected to evaluate their possibility as a nucleating agent for PLLA, these typical organic small molecule nucleating agents include benzoylhydrazine derivatives [28,29], oxalamide derivatives [30,31], 1H-benzotriazole derivatives [32,33], urea compounds [34,35], D-sorbitol [8], etc.…”

The Application of N, N -bis(Isonicotinic Acid) 1, 4-Naphthalenedicarboxylic Acid Dihydrazide in Biodegradable Poly(L-lactide): Crystalline Nucleation, Melting Behavior, Thermal Stability and Mechanical Properties

“…Similarly, this method can also be employed in PLLA as another semi-crystalline polymer. According to the category, the nucleating agents for PLLA are divided into inorganic nucleating agents and organic nucleating agents, the typical inorganic nucleating agents have silicate [22][23][24], metals phenylphosphonate [25,26] and nano oxide [27,28]; and the organic nucleating agents mostly focus on benzoylhydrazine derivatives [29,30], oxalamide derivatives [31,32], humic acid derivatives [33,34], 1H-benzotriazole derivatives [35,36], etc. Compared to the organic nucleating agents, a serious shortcoming of the inorganic nucleating agent is its poor compatibility with PLLA matrix, and surface modification technology is used to overcome this defect, but the surface modification can reduce the nucleation effect of inorganic matter to a certain extent [37].…”