Effect of Physical Factors during the Preparation of a Reaction Mixture in Turbulent Flows on the Rate of Butadiene Polymerization in the Presence of TiCl4-Al(i-C4H9)3 and Molecular Mass Characteristics of Butadiene Rubber

2019 ◽  
Vol 13 (2) ◽  
pp. 349-353
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenko ◽  
D. A. Shiyan ◽  
A. S. Ziganshina ◽  
G. M. Ganiev ◽  
...  
2014 ◽  
Vol 55 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Chansuree Chatarsa ◽  
Pattarapan Prasassarakich ◽  
Garry L. Rempel ◽  
Napida Hinchiranan

2004 ◽  
Vol 2 (1) ◽  
pp. 52-81 ◽  
Author(s):  
Yakov Estrin

AbstractBimodal molecular mass distribution (MWD) of polymers, obtained upon polymerization of hydrocarbon monomers in the nonpolar media under the action of dilithium initiators, is the consequence of separation of the reaction mixture into two phases. Bifunctional /living/ oligomers produce the insoluble sediment due to tetrameric association of the lithium active sites (the swollen gel-fraction). Part of the active site remains in the solution (the solfraction). Difference in the concentrations of the active sites into the phases leads to difference between the propagation rates of the /living/ chains and, as a result, to Bimodal MWD. The mathematical model of polymerization in the two-phase system is proposed. Satisfactory agreement between the calculations and the experiments is shown for butadiene polymerization in heptane under the action of 1,4-dilithiumpentane. Regulation of MWD up to the complete elimination of bimodality is possible via the programmed dosage of monomer and solvent into the reactor.


2019 ◽  
pp. 20-23
Author(s):  
E. N. Tkacheva ◽  
O. M. Trifonova ◽  
I. G. Akhmetov

The eff ect of butadiene rubber molecular parameters on conversion dependencies and viscosity characteristics of the process of graft copolymerization of styrene, microstructure and quality indicators of the synthesized samples of impact-resistant polystyrene was studied. It is testifi ed that an increase in the molecular mass of the elastomer does not aff ect the monomer conversion, however, it leads to a phase inversion shifting to the region of lower conversion degrees of styrene. In this case, an increase in the size of rubber particles and an increase in the content of the gel fraction are observed in the copolymer. The established changes in the microstructure correlate with the properties of high-impact polystyrene.


1990 ◽  
Vol 63 (01) ◽  
pp. 067-071 ◽  
Author(s):  
Joan C Castellote ◽  
Enric Grau ◽  
Maria A Linde ◽  
Nuria Pujol-Moix ◽  
Miquel LI Rutllant

SummaryIncreasing evidence suggests the involvement of leukocytes in the fibrinolytic system. Monocytes secrete pro-urokinase (Grau, Thromb Res 1989; 53: 145) and it has been shown that these cells have specific receptors for urokinase and plasminogen (Miles, Thromb Haemostas 1987; 58: 936). The aim of this study was to analyse the presence of plasminogen activator inhibitor(s) in platelet-free suspensions of human peripheral blood monocytes and polymorphonuclear leukocytes (PMN). SDS-PAGE and reverse fibrin autography showed an inhibitory band of 50 kDa in the monocyte extracts (Triton X-100) but not in the PMN extracts. Urokinase (u-PA) was mixed with increasing amounts of monocyte extract for 10 min and the mixtures were added to 125Ifibrin coated wells containing plasminogen. A dose-dependent decrease in the u-PA fibrinolytic activity was observed. The amount of inhibition increased when the monocyte releasates were preincubated with u-PA (40% inhibition after 5 min preincubation and 80% after 15 min), indicating a direct interaction between this activator and an inhibitor(s). After SDS-PAGE of monocyte extracts, immunoblotting and peroxidase staining identified both PAI1 and PAI2, with an apparent molecular weight of 47-50 kDa. Monocyte-associated PAI1 formed complexes with single chain t-PA with a molecular mass 50 kDa higher than the molecular mass of the free PAI1. However, a significant amount of PAI remained unbound to t-PA. This inactive PAI1 could have come from a rapid inactivation of the primary active PAI1. These PAI1 and PAI2 detected in human monocytes may be transcendent in the regulation of the fibrinolytic system.


TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 37-43 ◽  
Author(s):  
HANNU PAKKANEN ◽  
TEEMU PALOHEIMO ◽  
RAIMO ALÉN

The influence of various cooking parameters, such as effective alkali, cooking temperature, and cooking time on the formation of high molecular mass lignin-derived and low molecular mass carbohydrates-derived (aliphatic carboxylic acids) degradation products, mainly during the initial phase of softwood kraft pulping was studied. In addition, the mass transfer of all of these degradation products was clarified based on their concentrations in the cooking liquor inside and outside of the chips. The results indicated that the degradation of the major hemicellulose component, galactoglucomannan, typically was dependent on temperature, and the maximum degradation amount was about 60%. In addition, about 60 min at 284°F (140°C) was needed for leveling off the concentrations of the characteristic reaction products (3,4-dideoxy-pentonic and glucoisosaccharinic acids) between these cooking liquors. Compared with low molecular mass aliphatic acids, the mass transfer of soluble lignin fragments with much higher molecular masses was clearly slower.


2019 ◽  
Vol 13 (2) ◽  
pp. 115-123
Author(s):  
Ratu Mutialela Caropeboka

The environment is also called the natural environment is a phenomenon that forms around life rather than humans, either biotic or abiotic. The surrounding phenomenon that affects people is not limited to physical factors solely, on the contrary social factors play an important role to explain how human activity can affect the environment and the natural surroundings. The essence and falsafa of development is a change, growth and equity in all fields and dimensions to a better state. Development communication is part of a major process that requires social, economic, political and cultural change in line with the requirements of the local community. The simultaneous formulation of information dissemination carried out by radio, is no longer the only option of society, because the community has designed and determined what information they need. Television broadcasting has an influence on patterns of public action to model, imitate information gained through impressions. Community participation in safeguarding the environment to achieve harmonious and balanced development is the driving and driving force for social change to achieve sustainable development. Lingkungan disebut juga alam sekitar adalah fenomena yang wujud di sekeliling kehidupan daripada manusia,baik biotik ataupun abiotik. Fenomena sekeliling yang mempengaruhi manusia tidak terbatas kepada faktor fisikal semata-mata, sebaliknya faktor sosial turut berperanan penting bagi menerangkan bagaimana aktivitas manusia dapat mempengaruhi lingkungan dan alam sekitar. Hakikat dan Falasafah pembangunan ialah suatu perubahan, pertumbuhan dan pemerataan dalam segala bidang dan dimensinya menuju keadaan yang lebih baik. Komunikasi pembangunan merupakan bahagian dari proses besar yang menghendaki adanya perubahan sosial, ekonomi, politik dan budaya yang sejalan dengan persyaratan keperluan masyarakat lokal. Formula keserentakan penyebaran informasi yang dilakukan melalui radio, tidak lagi menjadi satu-satunya pilihan masyarakat, karena masyarakatlah telah merancang dan menentukan informasi apa yang mereka perlukan. Siaran televisi mempunyai pengaruh pada pola tindakan masyarakat untuk mencontoh, meniru informasi yang didapat melalui tayangan. Partisipasi masyarakat menjaga lingkungan untuk mewujudkan pembangunan yang serasi dan seimbang adalah penggerak dan pengarah bagi perubahan sosial untuk mewujudkan pembangunan yang berkelanjutan


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