Control of Alfin Rubber Molecular Weight

1965 ◽  
Vol 38 (1) ◽  
pp. 103-111 ◽  
Author(s):  
V. L. Hansley ◽  
H. Greenberg
Keyword(s):  
Molecular Weight ◽  
Pilot Plant ◽  
Continuous Processing ◽  
Molecular Weights ◽  
Solution Type ◽  
Pilot Plant Scale ◽  
Heat Build Up ◽  
Derivatives Of

Abstract Control of molecular weight of alfin catalyzed diene polymers has been demonstrated for polymers of butadiene, isoprene, styrene, piperylene and combinations of these. The 1,4-dihydro derivatives of benzene and naphthalene are effective molecular weight moderators. The known microstructure of alfin polymers remains unchanged with the use of these agents. Molecular weight controlled alfin gums process readily on standard rubber machinery. Oil extenders or softeners, although not necessary, are easily incorporated. The feasibility of continuous processing has been demonstrated for the production of catalyst, moderators and polymers on pilot plant scale. A wide series of polymers and copolymers at predetermined molecular weights and compositions have been produced in the same pilot plant. Alfin polybutadiene with limited amounts of styrene is essentially a solution type SBR. Alfin copolymers with styrene and/or isoprene have undergone preliminary road tests in tires. Wear and heat build-up data indicate performance to be intermediate between SBR and polybutadiene.

Isoprene and Rubber. Part 29. High Molecular Hydrorubbers

1932 ◽  
Vol 5 (2) ◽  
pp. 136-140
Author(s):  
H. Staudinger ◽  
W. Feisst
Keyword(s):  
Molecular Weight ◽  
Catalytic Reduction ◽  
Molecular Form ◽  
Average Molecular Weight ◽  
Molecular Size ◽  
Decomposition Products ◽  
Molecular Weights ◽  
Rubber Part ◽  
Derivatives Of ◽  
Suitable Process

Abstract The molecular concept in organic chemistry is based upon the fact that the molecules, whose existence is proved by vapor density determinations, enter into chemical reactions as the smallest particles. If now it is assumed that organic molecular colloids like rubber are dissolved in dilute solution in molecular form then it must be proved that in the chemical transposition of macromolecules as well no change in the size of the macromolecules occurs. In the case of hemicolloids, therefore for molecular colloids with an average molecular weight of 1000 to 10,000, this has been proved by the reduction of polyindenes, especially of polysterenes, to hydroproducts with the same average molecular weight, and also by the fact that cyclorubbers do not change their molecular weight upon autoöxidation. The molecular weights of hemi-colloidal hydrocarbons are therefore invariable. This is much more difficult to prove in the case of rubber, although there are many more ways in which unsaturated rubber can be transposed than the stable polysterenes, polyindenes, and poly cyclorubbers. In most of the reactions with rubber, as in its action with nitrosobenzene, oxidizing agents, hydrogen halides, and halogens, an extensive decomposition takes place as a result of the instability of the molecule, which is referred to in another work. Therefore derivatives of rubber are not formed, but derivatives of hemi-colloidal decomposition products. The catalytic reduction of rubber in the cold appears to be the most suitable process of making it react without changing its molecular size in order to prove that in a chemical transposition its molecular weight remains the same.

Organobismuth compounds. I. Studies on triphenylbismuth(V) derivatives, Ph3BiX2

1970 ◽  
Vol 48 (16) ◽  
pp. 2488-2493 ◽  
Author(s):  
R. G. Goel ◽  
H. S. Prasad
Keyword(s):  
Molecular Weight ◽  
Infrared Spectra ◽  
Molecular Species ◽  
Structural Features ◽  
Molecular Weights ◽  
Electrical Conductances ◽  
Conductance Data ◽  
Chemical Constitution ◽  
Derivatives Of ◽  
Coordinate Structures

Triphenylbismuth(V) acid derivatives of the type, Ph3BiX2, where X = halide, nitrate, cyanate, acetate, haloacetate, or cyanoacetate have been prepared. Infrared spectra (4000 to 200 cm−1 region), electrical conductances, and molecular weights of these compounds have been studied to elucidate their structural features and chemical constitution. The molecular weight and conductance data show that these compounds behave as molecular species in benzene or nitromethane. The infrared spectroscopic results also indicate non-ionic five-coordinate structures. Bi—X stretching frequencies have been assigned for the difluoride, dichloride, dinitrate, dicyanate, and diacetate. These frequencies occur in the region 410–240 cm−1.

A Method for Measuring the Self-Cementing Characteristics of Fly Ash Pastes

1987 ◽  
Vol 113 ◽  
Author(s):  
R. I. A. Malek ◽  
D. M. Roy
Keyword(s):  
Molecular Weight ◽  
Fly Ash ◽  
Liquid Chromatograph ◽  
Cement Pastes ◽  
Molecular Weights ◽  
Matching Process ◽  
Chromatographic Peaks ◽  
Liquid Chromatographic ◽  
Derivatives Of ◽  
Molecular Weight Fractions

SUMMARYThe development of an improved method of trimethylsilylation [1] made possible the assessment of different polysilicate fractions in hydrated cement pastes, as a means of structural characterization. Several laboratories have presented various gas-liquid chromatographic data on the polysilicate derivatives of C-S-H [2–5]. Identification of the different molecular weight fractions has been made, in most laboratories, by matching the gasliquid chromatographic peaks with the gel permeation chromatographic peaks. The success of this matching process is always dependent on type of instruments, length of columns and temperature range.In the present investigation, a mass spectrometer, in direct contact with the gas-liquid chromatograph, was used to identify the molecular weight of each of the fractions separated from the chromatograph. The technique was applied to determine the molecular weights and abundances of different polysilicate species in hydrated fly ash pastes.

scholarly journals Production of a PET//LDPE Laminate Using a Reversibly Crosslinking Packaging Adhesive and Recycling in a Small-Scale Technical Plant

Recycling ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 47
Author(s):  
Katharina M. A. Kaiser ◽  
Tanja Ginzinger
Keyword(s):  
Molecular Weight ◽  
Pilot Plant ◽  
Alder Reaction ◽  
Diels Alder ◽  
Infrared Spectrometry ◽  
Small Scale ◽  
Scanning Calorimetry ◽  
Melt Index ◽  
Diels Alder Reaction ◽  
Pilot Plant Scale

Multilayer packaging is an important part of the packaging market, but it is not recyclable with conventional methods since it is made of different thermodynamically immiscible materials. In this work, it was shown that it is possible to produce a PET//LDPE laminate in a pilot plant for lamination by using an adhesive consisting of maleimide- and furan-functionalized polyurethane prepolymers that cure through the Diels–Alder reaction. The material could then be delaminated in a small-scale recycling plant using a solvent-based recycling process by partially opening the Diels–Alder adducts through the influence of temperature. The PET and LDPE could be recovered without any adhesive residues before each material was regranulated, and in the case of the PE, a film was produced via cast film extrusion. The obtained PET granulate exhibited a slight, approximately 10%, decrease in molecular weight. However, since small amounts of LDPE could not be separated, compatibilization would still be required here for further use of the material. The obtained LDPE film was characterized by means of infrared spectrometry, differential scanning calorimetry, tensile testing, determination of the melt index, and molecular weight. The film showed lower crosslinking than usual for LDPE recycling and exhibited good mechanical properties. In this work, it was thus shown that upscaling of the laminate production with the modified adhesive and also its recycling at the pilot plant scale is possible and thus could be an actual option for recycling multilayer packaging.

Identification of High Molecular Weight Derivatives of Plasmic Digests of Cross-Linked Human Fibrin

1978 ◽  
Vol 40 (02) ◽  
pp. 368-376 ◽  
Author(s):  
E Regañon ◽  
V Vila ◽  
J Aznar
Keyword(s):  
Molecular Weight ◽  
Present Report ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Molecular Weights ◽  
Main Components ◽  
Derivatives Of ◽  
Β Chain ◽  
D Dimer ◽  
Different Molecular Weight

SummaryHighly cross-linked human fibrin was digested with plasmin and the nine main components (labelled initially 1 to 9) were detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The components of greater molecular weight, bands 1 and 2, which are identified with fragments Y dimer and Y-D (270,000 and 220,000) contain three subunits which are joined by disulphide bonds which originate from the α, β and γ-γ-chains of cross-linked fibrin. They show a reaction of partial identity against anti fibrinogen fragment D-sera and anti fibrinogen fragment E sera. Bands 3, 4 and 5 correspond to three species of fragment D-dimer and have molecular weights of 175,000,160,000 and 130,000. Each of these species differs in the size of the γ-γ-chain remnants, while all maintain the cross-link between the γ-γ-chains. The remnants of a and β-chains of cross-linked fibrin remain the same in all three species. The components of electrophoretic bands 6, 7 and 8 correspond to three fragments, each with a different molecular weight and with common antigenic components against anti fibrinogen fragment D-sera; these are called D6 (90,000), D7 (75,000) and D8 (65,000) and are formed by α- and β-chain remnants of equal molecular weight and by γ-chain remnants with a different molecular weight for each fragment. The last fragment to be identified, corresponding to electrophoretic band 9 (50,000 molecular weight) corresponds to fibrin fragment E. The present report is in agreement with previous studies of plasmin digestion of highly cross-linked fibrin, but differs from them in number of fragments D-dimer which appear during the digestion.

The Synthesis of Poly(arylene ether)s in Solution at Pilot-Plant Scale with Control over Molecular Weight and End-Group Composition

2002 ◽  
Vol 6 (5) ◽  
pp. 714-720 ◽  
Author(s):  
Timothy P. Bender ◽  
Richard A. Burt ◽  
Gord K. Hamer ◽  
Christine DeVisser ◽  
Paul F. Smith ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pilot Plant ◽  
Group Composition ◽  
Arylene Ether ◽  
Pilot Plant Scale ◽  
End Group

scholarly journals POLYFUNCTIONAL DINITROPHENYL HAPTENS AS REAGENTS FOR ELICITATION OF IMMEDIATE TYPE ALLERGIC SKIN RESPONSES

1962 ◽  
Vol 115 (4) ◽  
pp. 789-801 ◽  
Author(s):  
Charles W. Parker ◽  
Milton Kern ◽  
Herman N. Eisen
Keyword(s):  
Molecular Weight ◽  
Guinea Pig ◽  
Antibody Formation ◽  
Antibody Affinity ◽  
Molecular Weights ◽  
Allergic Skin ◽  
Cutaneous Reactions ◽  
Skin Responses ◽  
Derivatives Of ◽  
Induce Antibody

Dinitrophenyl derivatives of differing molecular weights and degrees of substitution have been contrasted with respect to their ability to elicit immediate type allergic responses and their capacity to induce antibody formation in the guinea pig. In contradistinction to dinitrophenyl-proteins, bis-DNP-lysine and DNP-polylysines (including a 100,000 molecular weight derivative) failed to induce antibody detectable by guinea pig passive cutaneous anaphylaxis. Dinitrophenyl-polylysines evoked urticarial responses non-specifically, but after succinylation were about as effective as dinitrophenyl-proteins in eliciting specific cutaneous reactions. An important factor influencing the effectiveness of bis-DNP-lysine in evoking specific wheal-and-erythema responses is antibody affinity for the dinitrophenyl-lysyl determinant.

Schiff Base Derivatives of Lanthanons / Synthesis of La(III) Pr(III) and Nd(III) Derivatives of Ethylenediamine Bis-2,4-pentanedione

1975 ◽  
Vol 30 (1-2) ◽  
pp. 50-54 ◽  
Author(s):  
S. K. Agarwal ◽  
J. P. Tandon
Keyword(s):  
Molecular Weight ◽  
Schiff Base ◽  
Butyl Alcohol ◽  
Exchange Reactions ◽  
Molecular Weights ◽  
Tetradentate Schiff Base ◽  
Schiff Base Derivatives ◽  
Tert Butyl Alcohol ◽  
Derivatives Of

The 1:1 and 2:3 molar reactions of La(III), Pr(III) and Nd(III) isopropoxides with the bifunctional tetradentate Schiff base, ethylenediamine bis-2,4-pentanedione [AA2(CH2)2H2] have been investigated in the medium of dry benzene.Ln(O-i-C3H7) [AA2(CH2)2] and Ln2[AA2(CH2)2]3 [where, Ln = La(III), Pr(III) or Nd(III) and AA2(CH2)2- 2 anion of the corresponding Schiff base, AA2(CH2)2H2] type of compounds have been obtained in almost quantitative yields and in a state of sufficient purity. The 1:1 derivatives have been shown to undergo exchange reactions with an excess of tert-butyl alcohol leading to the formation of Ln(O-tert-C4H9) [AA2(CH2)2] [where, Ln = La(III), Pr(III) or Nd(III)] type of derivatives. The ebullioscopic determination of molecular weights shows that the 1:1 derivatives are dimeric, whereas 2:3 derivatives are monomeric in boiling benzene. On the basis of elemental analysis, exchange reactions, molecular weight determinations and IR spectra, plausible structures for the resulting 1:1 and 2:3 complexes have been indicated.

Investigation by HPLC of the Catabolism of Recombinant Tissue Plasminogen Activator in the Rat

1988 ◽  
Vol 60 (01) ◽  
pp. 107-112 ◽  
Author(s):  
Roy Harris ◽  
Louis Garcia Frade ◽  
Lesley J Creighton ◽  
Paul S Gascoine ◽  
Maher M Alexandroni ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Half Life ◽  
Recombinant Tissue Plasminogen Activator ◽  
Rat Plasma ◽  
High Molecular Weight Complex ◽  
Molecular Weights ◽  
Major Activity ◽  
Tissue Plasminogen

SummaryThe catabolism of recombinant tissue plasminogen activator (rt-PA) was investigated after injection of radiolabelled material into rats. Both Iodogen and Chloramine T iodination procedures yielded similar biological activity loss in the resultant labelled rt-PA and had half lives in the rat circulation of 1 and 3 min respectively. Complex formation of rt-PA was investigated by HPLC gel exclusion (TSK G3000 SW) fractionation of rat plasma samples taken 1-2 min after 125I-rt-PA injection. A series of radiolabelled complexes of varying molecular weights were found. However, 60% of the counts were associated with a single large molecular weight complex (350–500 kDa) which was undetectable by immunologically based assays (ELISA and BIA) and showed only low activity with a functional promoter-type t-PA assay. Two major activity peaks in the HPLC fractions were associated with Tree t-PA and a complex having a molecular weight of ̴ 180 kDa. HPLC fractionation to produce these three peaks at various timed intervals after injection of 125I-rt-PA showed each to have a similar initial rate half life in the rat circulation of 4-5 min. The function of these complexes as yet is unclear but since a high proportion of rt-PA is associated with a high molecular weight complex with a short half life in the rat, we suggest that the formation of this complex may be a mechanism by which t-PA activity is initially regulated and finally cleared from the rat circulation.

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