Waste tire powder, as waste rubber WR was subjected to grafting with styrene (St) and maleic anhydride (MA). Hydrogen peroxide H2O2 was used to initiate the free radical copolymerization of St onto WR. A thermal initi...Waste tire powder, as waste rubber WR was subjected to grafting with styrene (St) and maleic anhydride (MA). Hydrogen peroxide H2O2 was used to initiate the free radical copolymerization of St onto WR. A thermal initiation was used in case of grafting of MA onto WR. Effect of initiator and monomer concentrations together with the influence of reaction temperature and reaction time were investigated. The grafting was estimated by weight, and the grafted copolymers were characterized by FT/IR, DSC and SEM to prove the grafting. It has found that the grafting increases with increase monomer and initiator concentrations. The increase in the reaction temperature and time also causes increasing levels of the grafted St and MA.展开更多
Scrap vulcanized rubber is amongst a bigger waste polymers. It does not decompose easily owing to its cross linked structure. Modification of scrap tires powder by the grafting with 2-acrylamido-2-methylpropanesulfoni...Scrap vulcanized rubber is amongst a bigger waste polymers. It does not decompose easily owing to its cross linked structure. Modification of scrap tires powder by the grafting with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) is described. The grafting is achieved through free radical initiation. The effects of different amount of monomer and initiator were examined. Also the influence of reaction time and temperature were investigated. The grafted waste rubber was characterized by FT/IR, SEM and DSC measurements. The proposed mechanism of the grafting reaction is discussed. From DSC and SEM studies of WR-g-AMPS compared with PAMPS and WR, the results show that the particle size and crystallinity were enhanced for the grafted copolymers. The obtained modified scraped tires will used as an ion exchanger for the future applications.展开更多
The present study was conducted to investigate the use of stearic acid-grafted carboxymethyl chitosan(SA-CMC) as a downregulator for trans- forming growth factor-β (TGF- β) and vascular endothelial growth factor (VE...The present study was conducted to investigate the use of stearic acid-grafted carboxymethyl chitosan(SA-CMC) as a downregulator for trans- forming growth factor-β (TGF- β) and vascular endothelial growth factor (VEGF) in Ehrlich ascites carcinoma (EAC)-bearing mice. The antitumor effect of stearic acid-grafted carboxymethyl chitosan was assessed by the estimation of TGF- β and VEGF in serum in addition to the estimation of tumor volume, median survival time (MST), percentage of increase in life span (ILS%) as well as the contents of total lipid, DNA and RNA in liver tissues. Hematological profiles (hemoglobin, red blood cells, and platelets) were also assessed. In addition, liver function tests and the redox status were estimated. TGF- β, VEGF, DNA, RNA, and malondialdehyde (MDA) levels, in addition to serum alanine transaminase (ALT) and gamma glutamyl transferase (GGT) activities as well as total white blood cells counts and tumor volume were all highly significantly increased (P < 0.001) in untreated EAC-bearing mice compared to controls. However, hematological profiles, total lipid in liver tissues and serum albumin were highly decreased in EAC-bearing mice compared to controls. All these parameters were restored to the normal levels in SA-CMC treated EAC-bearing mice com- pared to the untreated EAC-bearing mice. It is thus concluded that stearic acid-grafted carboxymethyl chitosan has a remarkable antitumor activity against EAC in Swiss albino mice through downregulation of TGF-β and VEGF.展开更多
文摘Waste tire powder, as waste rubber WR was subjected to grafting with styrene (St) and maleic anhydride (MA). Hydrogen peroxide H2O2 was used to initiate the free radical copolymerization of St onto WR. A thermal initiation was used in case of grafting of MA onto WR. Effect of initiator and monomer concentrations together with the influence of reaction temperature and reaction time were investigated. The grafting was estimated by weight, and the grafted copolymers were characterized by FT/IR, DSC and SEM to prove the grafting. It has found that the grafting increases with increase monomer and initiator concentrations. The increase in the reaction temperature and time also causes increasing levels of the grafted St and MA.
文摘Scrap vulcanized rubber is amongst a bigger waste polymers. It does not decompose easily owing to its cross linked structure. Modification of scrap tires powder by the grafting with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) is described. The grafting is achieved through free radical initiation. The effects of different amount of monomer and initiator were examined. Also the influence of reaction time and temperature were investigated. The grafted waste rubber was characterized by FT/IR, SEM and DSC measurements. The proposed mechanism of the grafting reaction is discussed. From DSC and SEM studies of WR-g-AMPS compared with PAMPS and WR, the results show that the particle size and crystallinity were enhanced for the grafted copolymers. The obtained modified scraped tires will used as an ion exchanger for the future applications.
文摘The present study was conducted to investigate the use of stearic acid-grafted carboxymethyl chitosan(SA-CMC) as a downregulator for trans- forming growth factor-β (TGF- β) and vascular endothelial growth factor (VEGF) in Ehrlich ascites carcinoma (EAC)-bearing mice. The antitumor effect of stearic acid-grafted carboxymethyl chitosan was assessed by the estimation of TGF- β and VEGF in serum in addition to the estimation of tumor volume, median survival time (MST), percentage of increase in life span (ILS%) as well as the contents of total lipid, DNA and RNA in liver tissues. Hematological profiles (hemoglobin, red blood cells, and platelets) were also assessed. In addition, liver function tests and the redox status were estimated. TGF- β, VEGF, DNA, RNA, and malondialdehyde (MDA) levels, in addition to serum alanine transaminase (ALT) and gamma glutamyl transferase (GGT) activities as well as total white blood cells counts and tumor volume were all highly significantly increased (P < 0.001) in untreated EAC-bearing mice compared to controls. However, hematological profiles, total lipid in liver tissues and serum albumin were highly decreased in EAC-bearing mice compared to controls. All these parameters were restored to the normal levels in SA-CMC treated EAC-bearing mice com- pared to the untreated EAC-bearing mice. It is thus concluded that stearic acid-grafted carboxymethyl chitosan has a remarkable antitumor activity against EAC in Swiss albino mice through downregulation of TGF-β and VEGF.
