Study on brittle ductile transition of impact stre

Research on brittle ductile transition of pen impact strength II

1.4 performance test and calculation

(1) determination of grafting rate

the market capacity of plastic extruder will be further expanded and purified: take the dry grafted sample of the control with no water cleaning and water cleaning, fully dissolve it in xylene, and then put it into acetone solution to precipitate it, put the purified grafted product in a vacuum oven, dry it at 40 ℃ to constant weight, and then use it

accurately weigh 0.4 g of the purified sample and add it to 50ml of xylene. After a little cooling, add 5.0 ml of 0.7 mol/L KOH ethanol solution. With thymol blue as the indicator, titrate it with 2.978 mol/L HCl isopropanol to the end point

grafting rate GX can be calculated according to formula (1):

gx = [(v1-v) n × 98.06／(2 × one hundred and three × W)] × 100% (1)

in the formula: V1 - the volume consumed by HCl isopropanol when measuring the graft, ml:

V - the volume consumed by HCl isopropanol in the blank experiment, ml:

n - the concentration of HCl isopropanol, mol/L

w -- weight of graft sample, G

(2) infrared characterization of grafts

dissolve the purified sample in CCl4 solution and test it with infrared spectrometer

(3) performance test of blends

impact performance shall be tested according to GB/T 1843-1996

2. Results and discussion

2.1 infrared spectrum characterization of grafted polymer

pure EPD connector company and electrical laboratory have actively carried out the research and development of connector technology suitable for AA (8000) series aluminum alloy conductors. See Figure 1 for the infrared spectrum of M and epdm-g-gma grafted polymer. By comparing Fig. 1a and Fig. 1b, it can be seen that the vibration absorption peak of propylene oxide appears near 1730.93cm-1 of Fig. 1b, indicating that the GMA group has been connected to the EPDM molecular chain

2.2 effect of the amount of DCP and GMA on the grafting rate

under the condition that the amount of EPDM and DCP is certain (EPI) m:dcp = 100:0.03], changing the amount of GMA can obtain the relationship between different amounts of GMA and the grafting rate, as shown in Figure 2. With a certain amount of EPDM and GMA (epdm:gma = 100:4), changing the amount of DCP can get the relationship between the amount of DCP and the grafting rate, as shown in Figure 3

it can be seen from Figure 2 that when the amount of EPDM and DC is constant, the grafting rate first increases rapidly, then slowly increases, and finally shows a downward trend with the increase of the amount of GMA. This is because when the amount of GMA monomer is low, with the increase of the amount, the collision opportunity between GMA and macromolecular free radicals increases, so the grafting rate increases; However, a large increase in the amount of GMA has little effect on the grafting rate. The grafting reaction mainly depends on the decomposition of DCP. When the concentration of DCP is constant, a large increase in the concentration of GMA has little effect on the grafting rate; On the contrary, when the amount of GMA is excessive, the unreacted GMA will remain in the graft, and GMA will be partially vaporized, which will reduce the grafting rate. (to be continued)