scholarly journals Delaminated Polymer/Lamellar Aluminophosphate Nanocomposites Prepared via in SITU Polymerization

2006 ◽  
Vol 15 (5) ◽  
pp. 096369350601500 ◽  
Author(s):  
Jingyu Wang ◽  
Guoping Chen ◽  
Quan Zhou
Keyword(s):  
Polymer Matrix ◽  
In Situ Polymerization ◽  
Short Chain ◽  
Long Chain

A method to synthesize completely delaminated polymer/lamellar aluminophosphate (Mu-4) nanocomposites has been successfully developed, wherein organo-modification of Mu-4 followed by in situ polymerization was applied. It can be found that the long chain n-dodecylamine molecules can favor the intercalation of Mu-4 and thus readily make the Mu-4 layers delaminated in the polymer matrix compared with the short chain N,N-dimethylpropane-1,3-diamine.

Synthesis and Characterizations of Poly(Butylene Succinate) Copolyester

2014 ◽  
Vol 1015 ◽  
pp. 381-384
Author(s):  
Li Liu ◽  
Li Hai Cai ◽  
Dan Liu ◽  
Jun Xu ◽  
Bao Hua Guo
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Crystallization Temperature ◽  
In Situ Polymerization ◽  
Nucleating Agent ◽  
Single Fiber ◽  
Butylene Succinate ◽  
Crystallization Behaviors ◽  
Polymerization Method

The poly (butylene succinate) (PBS) and 3 wt% attapulgite (ATP) reinforced PBS/ATP nanocomposites with 1,6-hexanediol were fabricated using an in situ polymerization method. The crystallization behaviors indicated that ATP had effectively acted as nucleating agent, resulting in the enhancement on the crystallization temperature. The SEM results showed a superior interfacial linkage between ATP and PBS. Also, ATP could disperse as a single fiber and embed in the polymer matrix, which resulted in the improved mechanical properties.

scholarly journals PA6 and Halloysite Nanotubes Composites with Improved Hydrothermal Ageing Resistance: Role of Filler Physicochemical Properties, Functionalization and Dispersion Technique

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 211 ◽  
Author(s):  
Valentina Sabatini ◽  
Tommaso Taroni ◽  
Riccardo Rampazzo ◽  
Marco Bompieri ◽  
Daniela Maggioni ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Polymer Matrix ◽  
In Situ Polymerization ◽  
Cost Effective ◽  
Polyamide 6 ◽  
Halloysite Nanotubes ◽  
Amide Bonds ◽  
Molecular Weights ◽  
Dispersion Technique

Polyamide 6 (PA6) suffers from fast degradation in humid conditions due to hydrolysis of amide bonds, which limits its durability. The addition of nanotubular fillers represents a viable strategy for overcoming this issue, although the additive/polymer interface at high filler content can become privileged site for moisture accumulation. As a cost-effective and versatile material, halloysite nanotubes (HNT) were investigated to prepare PA6 nanocomposites with very low loadings (1–45% w/w). The roles of the physicochemical properties of two differently sourced HNT, of filler functionalization with (3-aminopropyl)triethoxysilane and of dispersion techniques (in situ polymerization vs. melt blending) were investigated. The aspect ratio (5 vs. 15) and surface charge (−31 vs. −59 mV) of the two HNT proved crucial in determining their distribution within the polymer matrix. In situ polymerization of functionalized HNT leads to enclosed and well-penetrated filler within the polymer matrix. PA6 nanocomposites crystal growth and nucleation type were studied according to Avrami theory, as well as the formation of different crystalline structures (α and γ forms). After 1680 h of ageing, functionalized HNT reduced the diffusion of water into polymer, lowering water uptake after 600 h up to 90%, increasing the materials durability also regarding molecular weights and rheological behavior.

scholarly journals Characteristics of Newly Isolated Geobacillus sp. ZY-10 Degrading Hydrocarbons in Crude Oil

2015 ◽  
Vol 64 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Yumei Sun ◽  
Zhanguo Ning ◽  
Fan Yang ◽  
Xianzhen Li
Keyword(s):  
Crude Oil ◽  
Cellular Fatty Acid ◽  
Short Chain ◽  
Heavy Crude Oil ◽  
16S Rdna Sequence ◽  
Carbohydrate Fermentation ◽  
Heavy Crude ◽  
Production Tolerance ◽  
Long Chain

An obligately thermophilic strain ZY-10 was isolated from the crude oil in a high-temperature oilfield, which was capable of degrading heavy crude oil. Phenotypic and phylogenetic analysis demonstrated that the isolate should be grouped in the genus Geobacillus, which shared the highest similarity (99%) of the 16S rDNA sequence to Geobacillus stearothermophilus. However, the major cellular fatty acid iso-15:0 (28.55%), iso-16:0 (24.93%), iso-17:0 (23.53%) and the characteristics including indole production, tolerance to NaN3 and carbohydrate fermentation showed some difference from the recognized species in the genus Geobacillus. The isolate could use tridecane, hexadecane, octacosane and hexatridecane as sole carbon source for cell growth, and the digesting rate of long-chain alkane was lower than that of short-chain alkane. When the isolate was cultured in the heavy crude oil supplement with inorganic salts and trace yeast extract, the concentration of short-chain alkane was significantly increased and the content of long-chain alkane was decreased, suggesting that the larger hydrocarbon components in crude oil were degraded into shorter-chain alkane. Strain ZY-10 would be useful for improving the mobility of crude oil and upgrading heavy crude oil in situ.

The preparation of modified boehmite/PMMA nanocomposites by in situ polymerization and the assessment of their capability for Cu2+ ion removal

2016 ◽  
Vol 40 (4) ◽  
pp. 3612-3621 ◽  
Author(s):  
Gholamhossein Mohammadnezhad ◽  
Mohammad Dinari ◽  
Roozbeh Soltani
Keyword(s):  
Thermal Properties ◽  
Polymer Matrix ◽  
Active Sites ◽  
In Situ Polymerization ◽  
Ion Removal

The addition of nanoboehmite as a nanofiller into the polymer matrix led to the improvement of the thermal properties and increased the active sites of nanocomposites for Cu(ii) removal.

Preparation and Properties of Polyamide 6-Functionalized Nanometer-Sized Graphene Composite Fiber

2012 ◽  
Vol 519 ◽  
pp. 20-23 ◽  
Author(s):  
Hai Hui Liu ◽  
Wei Wei Peng ◽  
Yong Tan ◽  
Li Chen Hou ◽  
Xing Xiang Zhang
Keyword(s):  
Polymer Matrix ◽  
Polyphosphoric Acid ◽  
In Situ Polymerization ◽  
Reaction Medium ◽  
Polyamide 6 ◽  
Composite Fiber ◽  
Pristine Graphene ◽  
Nanocomposite Fiber ◽  
Novel Approach

A novel approach to the functionalization of nanometer-sized graphene was presented in this work. Covalent bonding between the filler and matrix was formed, with minimal disruption to the sp2 hybridization of the pristine graphene sheet. Functionalization proceeded by covalently bonding a 4-substituted benzoic acid monomer to the surface of expanded graphene, via ‘‘direct Friedel-Crafts” acylation in mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxide. Polyamide 6 (PA6)-functionalized graphene (FG) composites were prepared by in situ polymerization of ε-caprolactam in the presence of nanometer-sized FG. Nanocomposite fiber with 0.1 wt.% content of nanometer-sized FG was prepared with a piston spinning machine and hot-roller drawing machine. The nanometer-sized FG performed homogeneous dispersion in the polymer matrix. The mechanical properties of the PA6-FG composites fiber was enhanced by adding FG in the polymer matrix. The new functionalization method paves the way to prepare graphene-based nanocomposites fiber simply, without disrupting the primary structures of nanometer-sized graphene.

scholarly journals Oligofructose and long-chain inulin: influence on the gut microbial ecology of rats associated with a human faecal flora

2001 ◽  
Vol 86 (2) ◽  
pp. 291-300 ◽  
Author(s):  
Brigitta Kleessen ◽  
Ludger Hartmann ◽  
Michael Blaut
Keyword(s):  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Standard Diet ◽  
Faecal Flora ◽  
Gastrointestinal Health ◽  
Faecal Bacteria ◽  
C 50 ◽  
Butyrate Production ◽  
Long Chain

Dietary incorporation of fermentable, indigestible fructans may be of benefit to gastrointestinal health by providing short-chain fatty acids, stimulating the proliferation of bifidobacteria or lactobacilli and suppressing potential pathogenic organisms in the gut. We tested the hypothesis that the effects of fructans on caecal, colonic and faecal short-chain fatty acid concentration and microflora composition depend on their chain length. Germ-free rats associated with a human faecal flora were randomly assigned to one of four treatments as follows: (1) commercial standard diet as a control (Con); (2) Con+50 g short-chain oligofructose/kg (OF); (3) C+50 g long-chain inulin/kg (lcIN); or (4) Con+50 g OF–lcIN/kg (Mix OF–lcIN). Changes in bacterial population groups in response to feeding these diets were investigated with 16S rRNA-targeted probes applied inin situhybridization. Mix OF–lcIN- and lcIN-containing diets resulted in larger numbers of caecal, colonic and faecal bacteria of theClostridium coccoides–Eubacterium rectalecluster than Con (10·6 and 10·3v.9·5 log10/g wet wt), whereas OF alone did not affect this bacterial group in caecum, colon or faeces. A bifidogenic effect was only observed in the colon and faeces of OF-treated rats. More lactobacilli were found in caecal and colonic contents of Mix OF–lcIN-fed rats and in faeces of OF-fed rats compared with Con. Mix OF–lcIN and OF led to significantly smaller numbers of caecal, colonic and faecal bacteria belonging to theClostridium histolyticumandC. lituseburensegroups than Con (6·8 and 6·9v.7·9 log10/g wet wt). Counts of total bacteria,Bacteroides–PrevotellaandEnterobacteriaceaedid not differ between the groups. OF and/or lcIN-containing diets significantly increased the caecal and colonic concentration of butyrate and its relative molar proportion. Only lcIN-containing diets resulted in a higher faecal concentration of butyrate than Con. Higher molar proportions of faecal butyrate were observed with all diets that had been supplemented with OF and/or lcIN. Stimulation of butyrate production could be of interest for the prevention of ulcerative colitis and colon cancer.

Dynamic Mechanical Properties and Phase Structure of Polyethylene/Montmorillonite Nanocomposites Prepared by In Situ Polymerization

2013 ◽  
Vol 457-458 ◽  
pp. 293-296
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Polymer Matrix ◽  
Phase Structure ◽  
In Situ Polymerization ◽  
Conformational Transitions ◽  
Dynamic Mechanical Properties ◽  
Strong Interactions ◽  
Dynamic Mechanical

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The dynamic mechanical properties and phase structure of PE/MMT nanocomposites at different MMT concentrations (from 0.1 to 1.2 wt %) were studied. The storage modulus of PE/MMT nanocomposites is higher than that of the polymer matrix. And the motions of molecular relaxations and conformational transitions both in non-crystalline and crystalline phases are confined by the strong interactions between polymer and MMT. Otherwise, the spherulite size gradually decreases with the increasing content of MMT.

Preparation of a new polypropylene/clay nanocomposites via in situ polymerization

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Ghasem Naderi ◽  
Mehdi Nekoomanesh ◽  
Reza. Mehtarani ◽  
Hasan. Eslami
Keyword(s):  
Polymer Matrix ◽  
In Situ Polymerization ◽  
Low Frequency ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Pronounced Increase ◽  
Stress Overshoot ◽  
Internal Donor ◽  
Transmission Electron

AbstractNovel polypropylene/clay nanocomposites were prepared by in situ polymerization method with TiCl4/MgCl2/organoclay/internal donor- AlEt3 catalyst. The organo clay used is commercial Closite 15A that is an ammonium saltmodified montmorillonite (AMMT). For preparation of the catalyst, MgCl2 was deposited into the swollen AMMT layers and then TiCl4 and internal donor were loaded on the layer surfaces of AMMT. X-ray diffraction (XRD), transmission electron microscopy (TEM) and rheological measurements were used for characterization of the nanocomposites. The Linear and nonlinear melt-state viscoelastic properties of the polymer matrix and its nanocomposite are also investigated. In the presence of the clay lamellae, a pronounced increase in the low frequency moduli is observed. Transient rheological data reveal a stress overshoot for nanocomposite where there is no significant overshoot for polymer matrix. This stress overshoot can be attributed to the deformation and orientation of the special structure of clay platelets in polymer melts. Finally, experimental data are compared with the predictions of a mesoscopic rheological model.

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