Rheology and Structure of a Butadiene−Styrene Diblock Copolymer in Dibutyl Phthalate:  Role of Concentration Fluctuation in Disruption and Reformation of Micellar Lattice

2001 ◽  
Vol 34 (19) ◽  
pp. 6742-6755 ◽  
Author(s):  
Hiroshi Watanabe ◽  
Yumi Matsumiya ◽  
Toshiji Kanaya ◽  
Yoshiaki Takahashi
Keyword(s):  
Diblock Copolymer ◽  
Dibutyl Phthalate ◽  
Concentration Fluctuation ◽  
Butadiene Styrene

scholarly journals Novel Synthesis of Cellulose-Based Diblock Copolymer of Poly(hydroxyethyl methacrylate) by Mechanochemical Reaction

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Takeshi Ohura ◽  
Yusaku Tsutaki ◽  
Masato Sakaguchi
Keyword(s):  
Free Radical ◽  
Reaction Time ◽  
Diblock Copolymer ◽  
Room Temperature ◽  
Mechanochemical Reaction ◽  
Hydroxyethyl Methacrylate ◽  
Radical Chain ◽  
Mechanical Fracture ◽  
Novel Synthesis

The mechanical fracture of polymer produces polymeric free radical chain-ends, by which liner block copolymers have been synthesized. A diblock copolymer of microcrystalline cellulose (MCC) and poly 2-hydroxyethyl methacrylate (pHEMA) was produced by the mechanochemical polymerization under vacuum and room temperature. The fraction of pHEMA in MCC-block-pHEMA produced by the mechanochemical polymerization increased up to 21 mol% with increasing fracture time (~6 h). Then, the tacticities of HEMA sequences in MCC-block-pHEMA varied according to the reaction time. In the process of mechanochemical polymerization, cellulose could play the role of a radical polymerization initiator capable of controlling stereoregularity.

scholarly journals Compatibilizer Role of Styrene-butadiene-styrene Triblock Copolymer in Asphalt

2001 ◽  
Vol 33 (3) ◽  
pp. 209-213 ◽  
Author(s):  
Shingo Kamiya ◽  
Shigeru Tasaka ◽  
Xiaomin Zhang ◽  
Dewen Dong ◽  
Norihiro Inagaki
Keyword(s):  
Triblock Copolymer ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

Effect of Additive Constraint on the Morphological and Mechanical Properties of Triblock Copolymer Blends

1996 ◽  
Vol 461 ◽  
Author(s):  
L. Kane ◽  
D. A. Norman ◽  
S. A. White ◽  
R. J. Spontak
Keyword(s):  
Electron Microscopy ◽  
Diblock Copolymer ◽  
Triblock Copolymer ◽  
Morphological Characteristics ◽  
Mechanical Analysis ◽  
Molecular Weights ◽  
Copolymer Blends ◽  
Transmission Electron ◽  
Copolymer Blend

ABSTRACTWhile numerous studies have addressed the morphological characteristics of diblock copolymer blends either with a second copolymer or a parent homopolymer, relatively few have examined comparable blends containing a triblock copolymer. In this study, we investigate the role of mid-block bridging on the morphological and physical characteristics of blends composed of a poly(styrene-b-isoprene-b-styrene) (SIS) triblock copolymer with either an unconstrained homo-polyisoprene (hI) or an end-grafted SI diblock copolymer. Blend compositions and molecular weights of the hi, as well as the I-block of the copolymer, have all been systematically varied to elucidate the effect of additive constraint on the extent of nonideal intramicrodomain mixing. Blend morphologies are characterized using transmission electron microscopy, while blend properties have been measured by dynamic mechanical analysis.

Experimental cryptorchidism enhances testicular susceptibility to dibutyl phthalate or acrylamide in Sprague-Dawley rats

2019 ◽  
Vol 38 (8) ◽  
pp. 899-913 ◽  
Author(s):  
NP de Souza ◽  
AP Ferragut Cardoso ◽  
LMM Gomide ◽  
TRR Lima ◽  
HA Miot ◽  
...  
Keyword(s):  
Germ Cell ◽  
Dibutyl Phthalate ◽  
Reproductive Tract ◽  
In Utero ◽  
Seminiferous Tubules ◽  
Postnatal Exposure ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Extended Exposure

Cryptorchidism (CPT), the most common male congenital abnormality, is variably associated with other male reproductive tract problems. We evaluated if cryptorchid rats develop enhanced testicular susceptibility to dibutyl phthalate (DBP) or acrylamide (AA) after extended exposure. Three studies with rats were performed: (1) in utero and postnatal exposure to DBP or AA; (2) establishment of CPT and orchiopexy; and (3) in utero and postnatal exposures to DBP or AA associated with CPT/orchiopexy. Seminiferous tubules were histologically scored according to the severity of lesions: (1) Rats exposed to DBP (score 1.5) or AA (score 1.1) presented mostly preserved spermatogenesis. Some seminiferous tubules showed vacuolated germinative epithelium, germ cell apoptosis, and a Sertoli cell-only (SCO) pattern. (2) CPT (score 3.3) resulted in decreased absolute testes weights, degenerated and SCO tubules, and spermatogenesis arrest that were reversed by orchiopexy (score 1.1). (3) Exposure to DBP or AA with CPT/orchiopexy led to atrophic testes, spermatogenesis arrest, germ cell exfoliation/multinucleation, and SCO tubules (both chemicals score 2.5). Exposure to chemicals such as DBP or AA prevented the recovery of cryptorchid testes by orchiopexy. The possible role of environmental contaminants should be considered when looking for factors that modulate human testicular disorders associated with CPT.

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