scholarly journals In situ compatibilisation of alkenyl-terminated polymer blends using cross metathesis

RSC Advances ◽  
2015 ◽  
Vol 5 (13) ◽  
pp. 9658-9666 ◽  
Author(s):  
C. Descour ◽  
T. Macko ◽  
I. Schreur-Piet ◽  
M. P. F. Pepels ◽  
R. Duchateau
Keyword(s):  
Polymer Blends ◽  
Second Generation ◽  
Cross Metathesis ◽  
Macrophase Separation

A whiff of diblocks is enough! Straightforward coupling of two vinyl-terminated macromolecules was achieved by cross metathesis (CM) using Grubbs' second-generation catalyst (G2) giving access to a diversity of “self-compatibilised” polymer blends. Solution blends, in the absence of G2, showed clear macrophase separation while metathesized samples no longer did. A small fraction of diblocks only proved to act as an excellent compatibilizer.

scholarly journals In Situ Generation of Green Hybrid Nanofibrillar Polymer-Polymer Composites—A Novel Approach to the Triple Shape Memory Polymer Formation

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1900
Author(s):  
Ramin Hosseinnezhad ◽  
Iurii Vozniak ◽  
Fahmi Zaïri
Keyword(s):  
Polymer Blends ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Cellulose Nanofibers ◽  
Polymeric Materials ◽  
Novel Approach ◽  
Phase Transition Temperatures ◽  
Triple Shape Memory

The paper discusses the possibility of using in situ generated hybrid polymer-polymer nanocomposites as polymeric materials with triple shape memory, which, unlike conventional polymer blends with triple shape memory, are characterized by fully separated phase transition temperatures and strongest bonding between the polymer blends phase interfaces which are critical to the shape fixing and recovery. This was demonstrated using the three-component system polylactide/polybutylene adipateterephthalate/cellulose nanofibers (PLA/PBAT/CNFs). The role of in situ generated PBAT nanofibers and CNFs in the formation of efficient physical crosslinks at PLA-PBAT, PLA-CNF and PBAT-CNF interfaces and the effect of CNFs on the PBAT fibrillation and crystallization processes were elucidated. The in situ generated composites showed drastically higher values of strain recovery ratios, strain fixity ratios, faster recovery rate and better mechanical properties compared to the blend.

In situ compatibilized polypropylene/liquid crystalline polymer blends

Polymer ◽  
1996 ◽  
Vol 37 (18) ◽  
pp. 4099-4106 ◽  
Author(s):  
Yei-Po Chiou ◽  
Kuo-Chan Chiou ◽  
Feng-Chih Chang
Keyword(s):  
Polymer Blends ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer

scholarly journals In situ-DRIFTS study: influence of surface acidity of rhenium-based catalysts in the metathesis of various olefins for propylene production

RSC Advances ◽  
2017 ◽  
Vol 7 (61) ◽  
pp. 38659-38665 ◽  
Author(s):  
Siriporn Vorakitkanvasin ◽  
Weena Phongsawat ◽  
Kongkiat Suriye ◽  
Piyasan Praserthdam ◽  
Joongjai Panpranot
Keyword(s):  
Surface Acidity ◽  
In Situ Drifts ◽  
Cross Metathesis ◽  
Metathesis Reactions ◽  
Propylene Production

Various olefins including 1- and 2-butene, 2-pentene, and ethylene were used as the reactants for producing propylene by self- and cross-metathesis reactions at 60 °C on supported Re-based catalysts (4 wt% Re).

Influence of solid surface on the compatibility in polymer blends produced in situ

2006 ◽  
Vol 42 (11) ◽  
pp. 3102-3107 ◽  
Author(s):  
Y.S. Lipatov ◽  
T.D. Ignatova ◽  
L.F. Kosyanchuk ◽  
N.V. Yarovaya
Keyword(s):  
Polymer Blends ◽  
Solid Surface

Failure properties of 352 explanted silicone-gel breast implants

1996 ◽  
Vol 4 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Walter Peters ◽  
Dennis Smith ◽  
Stanley Lugowski
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Survival Curve ◽  
Breast Implants ◽  
Thick Wall ◽  
Thin Wall ◽  
Third Generation ◽  
Silicone Gel ◽  
Failure Properties

There have been three generations of silicone-gel breast implants. First generation implants (thick wall – thick gel with Dacron patches) were made from 1963 to 1972. Second generation implants (thin wall-thin gel) were made from 1972 until the mid 1980s. The introduction of third generation implants (stronger wall, low-bleed) was geographically dependent. In Canada, Dow Corning Silastic II implants were introduced in 1986, and Surgitek SCL implants were introduced in 1988. In the present study, a total of 352 silicone-gel breast implants were removed from 239 patients between 1981 and 1995. Their failure properties were dependent upon their generation (year of manufacture) and, for second generation implants, their duration in situ. Of the 352 implants, 20 were first generation, and all were fully intact. Twenty-eight were third generation implants, and 27 were fully intact. Failure properties of the 302 second generation implants were dependent upon their duration of implantation. A survival curve indicated that these implants began to fail (by leaking or rupturing) after four years in situ. By six years, 40% had failed. After 12 years, 95% had failed. Of the 171 second generation implants removed between 1991 and 1995, 77% had failed. The failure properties were similar for the three main manufacturers: Dow Corning, Heyer-Schulte and Surgitek. The failure rate for second generation implants is much higher than was previously believed. This is particularly significant in view of the current difficulty in diagnosing implant failure.

Effect of Rate and Timing of Biorational Materials for Control of Second Generation White Apple Leafhopper Nymphs, 1995

1996 ◽  
Vol 21 (1) ◽  
pp. 6-7
Author(s):  
E. H. Beers
Keyword(s):  
Second Generation ◽  
Apple Orchard ◽  
Tree Canopy ◽  
Single Tree ◽  
Tree Fruit ◽  
Pre Treatment ◽  
Experimental Treatments ◽  
Extension Center ◽  
Mature Apple

Abstract The test was conducted in a mature apple orchard (several strains of ‘Delicious’) at the Tree Fruit Research & Extension Center, Wenatchee, WA. Treatments were replicated 4 times, with each replicate consisting of a single tree. The experimental design was a RCB, using pre-treatment WALH populations as the blocking factor. The experimental treatments (three types of horticultural mineral oil and Neemix, a neem product) were applied at various rates and timings. The timings were selected based on previous experience of WALH phenology. The late Jul timing (27 Jul) coincides with the appearance of the 4th instars, while the mid-Aug timing (14 Aug) coincides with the first appearance of adults of the second generation. Pesticides were applied with a handgun sprayer to the point of drip. WALH populations were sampled ca. weekly by counting in situ all live nymphs on 20 leaves per tree, distributed throughout the tree canopy.

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