scholarly journals A Novel Synthesis of Branched High-molecular-weight (C40+) Long-chain Alkanes

2002 ◽  
Vol 66 (3) ◽  
pp. 523-531 ◽  
Author(s):  
Hans-Joachim LEHMLER ◽  
Robert G. BERGOSH ◽  
Mark S. MEIER ◽  
Robert M. K. CARLSON
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Novel Synthesis ◽  
Long Chain

Ligand-Unsymmetrical Phenoxyiminato Dinickel Catalyst for High Molecular Weight Long-Chain Branched Polyethylenes

2015 ◽  
Vol 4 (11) ◽  
pp. 1297-1301 ◽  
Author(s):  
Dongxu Shu ◽  
Aidan R. Mouat ◽  
Casey J. Stephenson ◽  
Anna M. Invergo ◽  
Massimiliano Delferro ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Long Chain

Behavior of Rubber Hydrocarbon in a Molecular Still

1939 ◽  
Vol 12 (4) ◽  
pp. 789-793 ◽  
Author(s):  
W. Harold Smith ◽  
Henry J. Wing
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
High Molecular Weight ◽  
Molecular Species ◽  
Decomposition Temperature ◽  
Sedimentation Equilibrium ◽  
Chain Molecules ◽  
Molecular Weights ◽  
Average Value ◽  
Long Chain

Abstract Some investigators believe that rubber consists of associated molecules, and others accept Staudinger's view that long-chain molecules are formed by polymerization. Pummerer, Andriessen and Gündel have obtained a molecular weight as low as 600. Meyer and Mark believe that it is approximately 5,000, although they calculated on the basis of osmotic pressures values as high as 350,000. They, as well as Pummerer, consider that rubber is an associated colloid and that high molecular weights are caused by aggregates, sometimes called micelles. Staudinger, however, considers that the long-chain rubber molecule itself has a molecular weight of 200,000 or even 350,000, and that products with lower values, which may be formed in rubber, result from degradation. if the molecules are small it might be possible to distil them if their vapor pressure could be sufficiently increased, but none would distil without decomposition if the molecules are very large. Because the vapor pressure of rubber below its decomposition temperature is low, it appeared of interest to attempt to distil the material in a molecular still. Paraffin wax and sugar, both substances of relatively high molecular weight, have been successfully distilled in this type of apparatus. Subsequent to the work described in this paper, the molecular weight of sol rubber prepared at this Bureau was determined by Kraemer and Lansing of E. I. du Pont de Nemours & Co., Inc. They used the Svedberg method of sedimentation equilibrium in an ultracentrifuge with ethereal solutions of sol rubber. The temperature of the solutions during determinations was approximately 10° C, and an average value of 460,000 was obtained. There was evidenced of a mixture of molecular species.

The composition of grape cuticle wax

1965 ◽  
Vol 18 (7) ◽  
pp. 1059 ◽  
Author(s):  
F Radler ◽  
DHS Horn
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Oleanolic Acid ◽  
Light Petroleum ◽  
Oxidation Products ◽  
Straight Chain ◽  
Neutral Alumina ◽  
Chain Lengths ◽  
Long Chain

The cuticle wax of the grape is composed of a soft wax (30%) readily removed by light petroleum and a hard wax (30%), mainly oleanolic acid, removed by chloroform. The soft wax of the fresh grape is composed chiefly of long-chain alcohols together with smaller amounts of aldehydes, esters, fatty acids, hydrocarbons, oleanolic acid, and small amounts of high molecular weight substances. The soft wax of dried grapes is similar in composition but contains no aldehydes and larger amounts of high molecular weight substances and oxidation products. The aldehydes, unusual wax components, are straight chain and range from C16 to C32 with the even chain-lengths predominating. They were destroyed by neutral alumina but can be chromatographed on silicic acid.

Effect of the biobased linear long-chain monomer on crystallization and biodegradation behaviors of poly(butylene carbonate)-based copolycarbonates

RSC Advances ◽  
2015 ◽  
Vol 5 (3) ◽  
pp. 2213-2222 ◽  
Author(s):  
Jie Zhang ◽  
Wenxiang Zhu ◽  
Chuncheng Li ◽  
Dong Zhang ◽  
Yaonan Xiao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Crystallization Property ◽  
Long Chain ◽  
High Molecular Weight Poly

In this work, high-molecular-weight poly(butylene carbonate)-based copolycarbonates with highly enhanced crystallization property were successfully prepared, by randomly copolymerizing with a biobased linear long-chain aliphatic diol.

Sign in / Sign up

Export Citation Format

Share Document