Determination of the phase diagram of HBA‐HNA liquid crystalline polymer/polycarbonate blends

Lee, Kam-Wa D.; Chan, Philip K.; Kamal, Musa R.

doi:10.1002/app.29103

Cited by 5 publications

(11 citation statements)

References 28 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The possibility of occurrence of TE during the blending process in the LCP/PC systems under consideration was investigated using nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy in our earlier work. The results of these investigations have been reported and discussed elsewhere (Lee et al, 2009). Therefore, they will not be discussed here.…”

Section: Resultsmentioning

confidence: 90%

“…Fig. 1B illustrates the changes in microscopic structure of the blends under various conditions (Lee et al, 2009). The small letters in Figs.…”

Section: Resultsmentioning

confidence: 98%

“…As in the case of many other polymer blend systems, these blends undergo phase separation with increasing temperature. Studies have been reported regarding the construction of phase diagrams (Kyu and Zhuang, 1988;Lee et al, 2009) and the temporal morphological development of these blends under quiescent conditions (Cohen-Addad et al, 1991;Kyu and Zhuang, 1988;Nagaya et al, 1989). However, to our knowledge, no studies have been reported regarding the effect of shear on the phase separation behavior in LCP/flexible polymer blends.…”

Section: Introductionmentioning

confidence: 84%

“…However, the phase separation temperatures and the phase-separated structures observed under shear are different from those under quiescent condition. In this work, T sp1 and T sp2 are determined visually from the real time microscopic images, according to the same set of criteria as those employed for studies under quiescent condition (Lee et al, 2009). It should be noted that quantitative determination of T sp2 from transmitted light intensity is not practical, when shear is applied.…”

Section: Microscopic Structures Under Shear Flowmentioning

confidence: 99%

“…Such LCP/PC blends are known to undergo phase separation with increasing temperature. As part of a comprehensive study of phase separation in LCP/PC systems, we reported results regarding the phase diagram and temporal morphological development for these blends under quiescent conditions (Lee et al, 2009). However, to our knowledge, the effect of shear on this system has not been investigated.…”

Section: Introductionmentioning

confidence: 96%

See 4 more Smart Citations

Phase Separation under Shear in Liquid Crystalline Polymer/Polycarbonate Blends

Lee

Kamal

Chan

2009

International Polymer Processing

View full text Add to dashboard Cite

The effect of low steady shear rates on the phase diagram and phase-separated morphology of liquid crystalline polymer (LCP)/polycarbonate (PC) blends was studied. Experiments were carried out with polarized light microscopy in conjunction with a shear stage for directly monitoring the phase separation behavior of the blends. Phase separation temperatures under shear flow were lower than those observed under quiescent conditions. Consequently, the phase diagram of the blend was shifted to a lower position, relative to the phase diagram obtained under quiescent conditions. The temporal morphological development of phase separation in the blends was also affected by the shear. Phase-separated structures were monitored, with and without shear, in blends containing 50 wt.% LCP. Results showed that the speed and amount of phase separation increased when shear was applied. The results indicate that these blends undergo shear-enhanced phase separation at low steady shear rates.

show abstract

Section: Resultsmentioning

confidence: 90%

“…Fig. 1B illustrates the changes in microscopic structure of the blends under various conditions (Lee et al, 2009). The small letters in Figs.…”

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 84%

Section: Microscopic Structures Under Shear Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 3 more Smart Citations

Phase Separation under Shear in Liquid Crystalline Polymer/Polycarbonate Blends

Lee

Kamal

Chan

2009

International Polymer Processing

View full text Add to dashboard Cite

show abstract

Thermally induced phase separation in liquid crystalline polymer/polycarbonate blends

Lee¹,

Chan²,

Kamal³

2010

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

Thermally induced phase separation in liquid crystalline polymer (LCP)/polycarbonate (PC) blends was investigated in this study. The LCP used is a main-chain type copolyester comprised of p-hydroxybenoic acid and 6-hydroxy-2-naphthoic acid. Specimens for microscopic observation were prepared by melt blending. The specimens were heated to a preselected temperature, at which they were held for isothermal phase separation. The preselected temperatures used in this study were 265, 290, and 300 C. The LCP contents used were 10, 20, and 50 wt %. These parameters corresponded to different positions on the phase diagram of the blends. The development of the phase-separated morphology in the blends was monitored in real time and space. It was observed that an initial rapid phase separation was followed by the coarsening of the dispersed domains. The blends developed into various types of phase-separated morphology, depending on the concentration and temperature at which phase separation occurred. The following coarsening mechanisms of the phase-separated domains were observed in the late stages of the phase separation in these blends: (i) diffusion and coalescence of the LCPrich droplets; (ii) vanishing of the PC-rich domains following the evaporation-condensation mechanism; and (iii) breakage and shrinkage of the LCP-rich domains.

show abstract

A Review: Current Status and Emerging Developments on Natural Polymer‐Based Electrospun Fibers

Han

Wang

et al. 2022

Macromol. Rapid Commun.

View full text Add to dashboard Cite

In recent years, natural polymer‐based electrospun fibers (EFs) with huge specific surface area, good biocompatibility, and biological activity obtained from electrospinning process exhibit tremendous vitality in the field of biomedical areas. Herein, the parameters of electrospinning from two perspectives, polymer solution such as solvent, polymeric relative molecular mass, concentration, viscosity, and conductivity of the solution, and electrospinning process such as spinning voltage, spinning flow rate, needle tip to collector distance, temperature, and humidity are first detailed. Next, the raw materials consisting of polysaccharides such as cellulose, hyaluronic acid, alginate, and chitosan as well as proteins such as collagen, gelatin, silk fibroin, and keratin are summarized. The preparation method and related characteristics of EFs with multistage structures such as porous, core–shell, Janus, bamboo‐like and other structures are introduced. The biomedical applications of these natural polymer‐based EFs mainly including tissue engineering, drug sustained release, wound dressings, and biomedical sensors are systematically recapitulated. Finally, the outlook on natural EFs is further proposed.

show abstract

Determination of the phase diagram of HBA‐HNA liquid crystalline polymer/polycarbonate blends

Cited by 5 publications

References 28 publications

Phase Separation under Shear in Liquid Crystalline Polymer/Polycarbonate Blends

Phase Separation under Shear in Liquid Crystalline Polymer/Polycarbonate Blends

Thermally induced phase separation in liquid crystalline polymer/polycarbonate blends

A Review: Current Status and Emerging Developments on Natural Polymer‐Based Electrospun Fibers

Contact Info

Product

Resources

About