Permeability of A Liquid Crystalline Epoxy

2001 ◽  
Vol 709 ◽  
Author(s):  
Jianxun Feng ◽  
Elliot P. Douglas
Keyword(s):  
Liquid Crystalline ◽  
Barrier Properties ◽  
Two Phase ◽  
Solubility Coefficient ◽  
Epoxy Network ◽  
Liquid Crystalline Epoxy ◽  
Smectic Mesophase ◽  
Liquid Crystalline Thermoset ◽  
Epoxy Systems ◽  
Main Factor

ABSTRACTThis paper presents a comparison of moisture permeation in liquid crystalline and conventional epoxy systems. The permeability is obtained using a dynamic method. It is found that both epoxy systems exhibit Fickian behavior. The liquid crystalline epoxy network exhibits higher barrier properties for moisture transport than the conventional epoxy network. The efficient chain packing within the smectic mesophase of the liquid crystalline thermoset (LCT) is suggested as the main factor for this difference. The stoichiometry has a large effect on the moisture permeation. The diffusion coefficient decreases monotonically with increasing amine/epoxide functional ratio. The permeability (P) and solubility coefficient (S) reach a minimum at a functional ratio of one. The mechanism of the permeation is described in terms of the two-phase morphology present and hydrogen bonding between absorbed water and the network.

Barrier properties and structure of liquid crystalline epoxy and its nanocomposites

Polymer ◽  
2018 ◽  
Vol 142 ◽  
pp. 109-118 ◽  
Author(s):  
YuanQiao Rao ◽  
Andong Liu ◽  
Kathleen O'Connell
Keyword(s):  
Liquid Crystalline ◽  
Barrier Properties ◽  
Liquid Crystalline Epoxy ◽  
Structure Of Liquid

Solution Properties and Phase Behavior of Ammonium Hexylene Octyl Succinate in Water and Water-Oil System

1970 ◽  
Vol 3 (1) ◽  
Author(s):  
Md. Hamidul Kabir ◽  
Ravshan Makhkamov ◽  
Shaila Kabir
Keyword(s):  
Critical Micelle Concentration ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Carbon Number ◽  
Phase Region ◽  
Solution Properties ◽  
Middle Phase ◽  
Two Phase ◽  
Lamellar Liquid Crystal ◽  
Drug Ingredient

The solution properties and phase behavior of ammonium hexylene octyl succinate (HOS) was investigated in water and water-oil system. The critical micelle concentration (CMC) of HOS is lower than that of anionic surfactants having same carbon number in the lipophilic part. The phase diagrams of a water/ HOS system and water/ HOS/ C10EO8/ dodecane system were also constructed. Above critical micelle concentration, the surfactant forms a normal micellar solution (Wm) at a low surfactant concentration whereas a lamellar liquid crystalline phase (La) dominates over a wide region through the formation of a two-phase region (La+W) in the binary system. The lamellar phase is arranged in the form of a biocompatible vesicle which is very significant for the drug delivery system. The surfactant tends to be hydrophilic when it is mixed with C10EO8 and a middle-phase microemulsion (D) is appeared in the water-surfactant-dodecane system where both the water and oil soluble drug ingredient can be incorporated in the form of a dispersion. Hence, mixing can tune the hydrophile-lipophile properties of the surfactant. Key words: Ammonium hexylene octyl succinate, mixed surfactant, lamellar liquid crystal, middle-phase microemulsion. Dhaka Univ. J. Pharm. Sci. Vol.3(1-2) 2004 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

scholarly journals Advances in Liquid Crystalline Epoxy Resins for High Thermal Conductivity

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1302
Author(s):  
Younggi Hong ◽  
Munju Goh
Keyword(s):  
Thermal Conductivity ◽  
Network Structure ◽  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Random Network ◽  
Three Dimensional ◽  
Heat Insulator ◽  
Liquid Crystalline Epoxy ◽  
Thermally Conductive ◽  
Substantial Interest

Epoxy resin (EP) is one of the most famous thermoset materials. In general, because EP has a three-dimensional random network, it possesses thermal properties similar to those of a typical heat insulator. Recently, there has been substantial interest in controlling the network structure of EP to create new functionalities. Indeed, the modified EP, represented as liquid crystalline epoxy (LCE), is considered promising for producing novel functionalities, which cannot be obtained from conventional EPs, by replacing the random network structure with an oriented one. In this paper, we review the current progress in the field of LCEs and their application to highly thermally conductive composite materials.

The effect of stoichiometry on the fracture toughness of a liquid crystalline epoxy

2002 ◽  
Vol 42 (2) ◽  
pp. 269-279 ◽  
Author(s):  
Elizabeth J. Robinson ◽  
Elliot P. Douglas ◽  
John J. Mecholsky
Keyword(s):  
Fracture Toughness ◽  
Liquid Crystalline ◽  
Liquid Crystalline Epoxy

Reinforcement in the mechanical properties of shape memory liquid crystalline epoxy composites

2015 ◽  
Vol 132 (40) ◽  
pp. n/a-n/a ◽  
Author(s):  
Huilong Guo ◽  
Yinwen Li ◽  
Jian Zheng ◽  
Jianqun Gan ◽  
Liyan Liang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Liquid Crystalline ◽  
Epoxy Composites ◽  
Liquid Crystalline Epoxy

Synthesis of Three Novel Aromatic Biazomethine Liquid- Crystalline Epoxy Resins and Curing Reaction with Aromatic Diamine

2011 ◽  
Vol 216 ◽  
pp. 34-38
Author(s):  
Jun Gang Gao ◽  
Xiao Na Zhang ◽  
Yong Gang Du
Keyword(s):  
Melting Point ◽  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Diphenyl Ether ◽  
Hydroxyl Group ◽  
Aromatic Diamine ◽  
Curing Reaction ◽  
Ozawa Equation ◽  
Liquid Crystalline Epoxy ◽  
Clearing Temperature

Three class of novel liquid crystalline epoxy resins containing azomething groups: N,N’-Bis[4-(2,3-epoxypropoxy)benzylidene]-4,4-diamino-diphenyl ether (p-BEPBDDE), N,N’-Bis[4-(2,3-epoxypropoxy)benzylidene]-4,4-diamino-diphenyl methane (p-BEPBDDM) and N,N’-Bis[(4-(2,3-epoxypropoxy)-benzyliden)-1,4- phenylene diamine] (p-BEPBPD) were synthesized and characterized. The results show that p-BEBDDE and p-BEBDDM belong to smectic texture and melting point is 239.5 and 178 oC, respectively. The p-BEPBD is nematic texture between its melting temperature (Tm) of 192 oC and clearing temperature (Ti) of 238 oC. The curing reaction can be described by Ozawa equation, and the alcohol-hydroxyl group can accelerate the curing reaction and decrease Ea in DSC experiment.

Sign in / Sign up

Export Citation Format

Share Document