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phosphorus-containing ame retardant plasticizers based on mL) and cation exchange resin catalyst (4.7 g) were added, aer
castor oil as a secondary plasticizer were synthesized and the that 30% hydrogen peroxide (39.7 g) was added dropwise to the
results showed that the material added plasticizers had reaction mixture over 2 h and then stirred for 5 h. Then the
improved tensile strength, with good heat insulation and ame reaction mixture was ltered to recycle the cation exchange
retardant properties, but the elongation at break was resin, and the remaining uid was washed to pH ¼ 7 with
decreased.18–21
sodium carbonate solution and distilled water. Then the water
Our team has conducted a substantial amount of work on and solvent were removed by vacuum distillation.
the synthesis of plasticizers, especially in clean production
processes.22–24 In this study, we synthesized ve environment-
friendly plasticizers derived from castor oil through mild
esterication/epoxidation reactions. The synthetic plasticizers
were added to PVC (along with a heat stabilizer), and the
properties were investigated and compared to the commercial
plasticizers DOTP and ESO. We compared the effects of epoxy
groups and carbon–carbon double bonds, ester groups and
hydroxyl groups, and alkyl and benzene rings on plasticizing
Synthesis of benzoyl castor oil (BCO)
Castor oil (93.4 g), benzoyl chloride (38.0 g), calcium oxide (10.6
g) and toluene (100 mL) were added to a 500 mL four-necked
ask and were stirred at 110 ꢀC for 3 h. Then the reaction
mixture was washed to pH ¼ 7 with sodium hydroxide solution
and distilled water. Then the water and solvent were removed by
vacuum distillation.
PVC to attempt to nd an environment-friendly plasticizer with
good plasticity ability using a simple synthesis method. We
expect more competitive results compared with traditional
plasticizers to lead the way towards green and sustainable
routes for PVC application.
Synthesis of epoxy benzoyl castor oil (EBCO)
BCO (121.5 g), acetic acid (18.0 g), toluene (100 mL) and cation
exchange resin catalyst (4.7 g) were added to a 500 mL four-
necked ask and were heated and 30% hydrogen peroxide
(39.7 g) was added dropwise to the reaction mixture over 2 h and
stirred at 60 ꢀC for 5 h. Then the reaction mixture was ltered to
recycle the cation exchange resin, and the remaining uid was
washed to pH ¼ 7 with sodium carbonate solution and distilled
water. Then the water and toluene were removed by vacuum
distillation.
Experimental section
Materials
Hydrogen peroxide, acetic anhydride, benzoyl chloride, acetic
acid, calcium oxide, toluene, sodium hydroxide, sodium
carbonate, hydrochloric acid and acetone were provided by
Nanjing Chemical Reagent Co., Ltd. (China); castor oil and the
cation exchange resin were provided by Anhui Xinyuan Chem-
ical Co., Ltd. (China).
Preparation of plasticized PVC samples
The PVC, plasticizer and heat stabilizer were mixed in the ratio
of 50 : 25 : 1. The mixture was blended for 7 min at 170 ꢀC using
a HAAKE PolyLab OS torque rheometer, and then placed in
a at-panel curing machine and pressed for 4 min at 170 ꢀC and
2 min at room temperature. The PVC blends were labeled as
PVC-DOTP (PVC/DOTP), PVC-ESO (PVC/ESO), PVC-ECO (PVC/
ECO), PVC-ACO (PVC/ACO), PVC-EACO (PVC/EACO), PVC-BCO
(PVC/BCO) and PVC-EBCO (PVC/EBCO).
Synthesis of epoxy castor oil (ECO)
Castor oil (93.4 g), acetic acid (18.0 g), toluene (100 mL) and
cation exchange resin catalyst (4.7 g) were added to a 500 mL
four-necked ask equipped with a stirrer, a thermometer,
a constant pressure funnel and a ball condenser, 30% hydrogen
peroxide (39.7 g) was dropwise added in the reaction mixture
over 2 h and stirred at 60 ꢀC for 5 h. Then the reaction mixture
was ltered to recycle the cation exchange resin, and the
remaining uid was washed to pH ¼ 7 with sodium carbonate
solution and distilled water. Then the water and solvent were
removed by vacuum distillation. Scheme 1 shows the synthesis
routes of all products.
Characterizations and measurements
FT-IR spectra were recorded on a Nicolet FTIR-360 (Nicolet
Instrument Corp., USA) Fourier transform infrared spectro-
photometer. The spectra was acquired in the range of 400 to
4000 cmꢁ1
.
1H NMR spectra were recorded by using an AVANE400
(Bruker Company, Switzerland) with deuterated chloroform as
a solvent.
Synthesis of acetylated castor oil (ACO)
Castor oil (93.4 g) and acetic anhydride (27.5 g) were added to
ꢀ
a 500 mL four-necked ask, and were stirred at 140 C for 2 h.
Tensile strength and elongation at break of all PVC samples
were determined according to the GB/T 1040.1-2006 (China)
under ambient conditions by using an E43.104 Universal
Testing Machine (MTS Instrument Corp., China).
The volatility stability tests were determined by GB/T 3830-
Then the reaction mixture was washed to pH ¼ 7 with sodium
carbonate solution and distilled water. Then the water was
removed by vacuum distillation.
Synthesis of epoxy acetylated castor oil (EACO)
2008, PVC samples were cut into 50 mm ꢂ 50 mm squares,
ꢀ
Castor oil (93.4 g) and acetic anhydride (27.5 g) were added to placed in an oven for 24 h at 80 C, and then cooled to room
ꢀ
a 500 mL four-necked ask and were stirred at 140 C for 2 h. temperature in a desiccator. The mass changes were measured
Then the reaction mixture was cooled to 60 ꢀC, and toluene (100 by weighing before and aer heating. The volatility rate was
10050 | RSC Adv., 2019, 9, 10049–10057
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