scholarly journals Prominent Crystallization Promotion Effect of Montmorillonite on PTT/PC Blends with PTT as the Continuous Phase

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 541
Author(s):  
Meiling Xue ◽  
Yingjie Liu ◽  
Kanghui Lv ◽  
Shaowu Han ◽  
Shengqiang Gao ◽  
...  

To regulate the crystallization of poly(trimethylene terephthalate) (PTT) retarded by melt blending with polycarbonate (PC), the crystallization of the PTT/PC blend was investigated employing nano-montmorillonite (MMT) as a crystallization promoter with PTT as the continuous phase. The results showed that MMT exhibits a significant promoting effect on PTT crystallization; the presence of 1 wt. % MMT shifts the initial and peak crystallization temperatures of the 70/30 PTT/PC blend to ~17 °C and ~32 °C, respectively. Additionally, the full width at half maximum (FWHM) narrows by ~45%, and the ΔHc increases by 3.7 J.g−1. The accelerating effect of MMT is determined by its distribution and dispersion which depends on the shear intensity, mixing mode, and loading. MMT is easier to exfoliate via the two-step method than by the one-step method. The distribution in the PTT phase is enriched along the phase interface forming an MMT layer. This endows sections of the PTT with abundant nuclei and thus crystallization is promoted markedly compared with the one-step method. Moreover, the finer MMT migrates more readily to the interface to cause a much smoother phase interface. However, a secondary crystallization peak appears when the shear force is not sufficient enough to make MMT finely dispersed, in case of the two-step method and the MMT content is increased to 3 wt. %. The mixing temperature shows little effect on the acceleration of MMT on the crystallization of PTT/PC compared with the shear force. Only when MMT did not exfoliate or uncomplete did the presence of epoxy resin help to promote crystallization because of the improved MMT dispersion.

1990 ◽  
Vol 9 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Sander Greenland ◽  
Alberto Salvan
Keyword(s):  
One Step ◽  

2013 ◽  
Vol 1546 ◽  
Author(s):  
Robert Dorresteijn ◽  
Robert Haschick ◽  
Kevin Müller ◽  
Markus Klapper ◽  
Klaus Müllen

ABSTRACTIn nonaqueous emulsion, moisture-sensitive polymerizations are performed in order to generate nanoparticles, which are not accessible by common aqueous emulsion polymerization. A nonaqueous emulsion, consisting of two immiscible aprotic organic solvents, is stabilized by amphiphilic block copolymers, such as PIb-PEO or PIb-PMMA copolymer, and lead to formation of nanosized dispersed droplets. They act as dispersed “nanoreactors” for the one-step synthesis of poly(urethane) nanoparticles in a polyadditon reaction as well as poly(L-lactide) nanoparticles through ring-opening polymerization, catalyzed by a moisture-sensitive catalyst. The well-dispersed particles possess average diameters below 100 nm and have narrow size distributions owing to the long-term stability of the dispersed droplets in the continuous phase.


2018 ◽  
Vol 54 (68) ◽  
pp. 9438-9441 ◽  
Author(s):  
Nathalie M. Pinkerton ◽  
Khadidja Hadri ◽  
Baptiste Amouroux ◽  
Leah Behar ◽  
Christophe Mingotaud ◽  
...  

A novel, one-step method for the synthesis of functional, organic–inorganic hybrid nanoparticles is reported.


Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 658 ◽  
Author(s):  
Xiaohui Yang ◽  
Yi Liu ◽  
Chunjie Yan ◽  
Ronghua Peng ◽  
Hongquan Wang

Geopolymer-TiO2 nanocomposites were prepared by two different techniques, namely the two-step acidification calcination treatment and one-step adding method. The potential photocatalytic activities of geopolymer-TiO2 nanocomposites prepared by the two different methods were tested and compared. Nanocomposites prepared via the one-step process showed better photocatalytic activity. The amount of TiO2 particles loaded on the surface of the foaming materials was investigated by XRD and SEM-Mapping. By comparing with the sample obtained from two-step treatment, the TiO2 particles were distributed uniformly on the surface of the foaming materials for the sample obtained from the one-step method in this study. Results showed that the specific surface area of the geopolymer-TiO2 prepared by the one-step treatment process (28.67 m2/g) was significantly lower than the two-step acidification calcination process (215.04 m2/g), while the photocatalytic efficiency with methylene blue trihydrate (MB) was better. This is due to the more stable structure of geopolymer-TiO2 nanocomposites, the better dispersion and more loading of TiO2 particles on the foaming materials surfaces, leading to the enhanced photocatalytic activity.


Author(s):  
George W. Patrick ◽  
Charles Cuell ◽  
Raymond J. Spiteri ◽  
William Zhang

In the formalism of constrained mechanics, such as that which underlies the SHAKE and RATTLE methods of molecular dynamics, we present an algorithm to convert any one-step integration method to a variational integrator of the same order. The one-step method is arbitrary, and the conversion can be automated, resulting in a powerful and flexible approach to the generation of novel variational integrators.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7604
Author(s):  
Hasan Shabbir ◽  
Tomasz Tokarski ◽  
Ditta Ungor ◽  
Marek Wojnicki

In this work, we report the synthesis method of carbon quantum dots (CDs) using the one-step method for fast and effective metal ion determination. Ascorbic acid was used as an inexpensive and environmentally friendly precursor. High-pressure and high-temperature reactors were used for this purpose. Microscopic characterization revealed the size of CDs was in the range of 2–6 nm and they had an ordered structure. The photoluminescence properties of the CDs depend on the process temperature, and we obtained the highest PL spectra for 6 h of hydrothermal reaction. The maximum emission spectra depend poorly on synthesis time. Further characterization shows that CDs are a good contender for sensing Fe3+ in aqueous systems and can detect concentrations up to 0.49 ppm. The emission spectra efficiency was enhanced by up to 200% with synthesis time.


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