GPC-IR High Temperature Gel Permeation Chromatograph Product Introduction

GPC-IR high-temperature gel permeation chromatograph is a fully automatic high-temperature GPC instrument developed by Spanish Polymer Char for polyolefin research, considering the shortcomings of high-temperature GPC in the market and combining years of experience of developers. The instrument can directly measure the value of methyl number per thousand carbon or the information of branching degree while determining the molecular weight and distribution of polyolefin. The analysis time of each sample is about 30 minutes. At the end of the analysis of the previous sample, the next sample is dissolved and waits for injection, which can greatly save time.

1. GPC-IR features:

1) Equipped with an autosampler to analyze 42 samples in turn;

2) IR4 or IR5MCT detector, the concentration information of the test sample can obtain the molecular weight of the sample and its distribution information;

3) The optional IR4 component probe or IR5MCT can directly measure CH3/1000C or short chain branch information;

4) The four-bridge viscosity detector is selected, and the long-chain branch information of the sample can be obtained by combining the Mark-flood temperature curve;

5) the selection of laser light scattering detector, can obtain the absolute molecular weight of the sample and other information;

6) Multiple injections can be performed without diluting the sample;

7) Built-in GPC-One software can control, receive and process signals from multiple detectors at the same time;

8) with remote control and interactive diagnosis function.

2. GPC-IR instrument has three major characteristics:

1. Fully automatic sample preparation and analysis system
1) Fully automatic sample preparation: manual only need to weigh the solid sample, and then put the sample into the sample bottle of the autosampler. With in-line filter and backwash function, no external filtration is required.
2) Automatic analysis process: After the sample is placed, there is no need to directly contact the solvent to protect the health of the operator. After the analysis is completed, the relevant pipelines are automatically cleaned to wait for the analysis of the next sample, which is fully in line with HSE standards.
3) New design to reduce degradation: the autosampler is divided into normal temperature area and high temperature area. Generally, the sample is located in the normal temperature area and the temperature is controlled by the program. The sample bottle is transferred to the high temperature area in turn according to the software program to ensure the same heating time of each sample. The sample is oscillated and dissolved to reduce shear degradation. Equipping nitrogen purge accessories can deoxidize nitrogen and minimize high temperature oxidation degradation.
4) On-line flow marker addition system: This system is selected and can automatically add flow markers. After its peak appears, the analysis program has been completed.

2. Infrared detector (IR4 or IR5MCT)
1) A special selective infrared detector, IR4 or IR5MCT detector only responds to C- H infrared absorption, with stable baseline, high selectivity and good repeatability.
2) high sensitivity: it can meet the MMD analysis of very dilute polyolefin solution, at a concentration of 0.125 mg/ml, the signal to noise ratio can reach 60.
3) While measuring the molecular weight and its distribution, the value of the number of kilo-carbon methyl groups or the information of short chain branches can also be directly measured, especially for the analysis of HDPE pipe material with low number of kilo-carbon methyl groups (the detection limit of IR5MCT detector components is less than 1); Combined with a viscosity detector, the information of long chain branches can also be obtained.

3. Independent column temperature control system
GPC-IR using different temperature control zone control, separate temperature control. The gel chromatography column is installed separately in the column temperature box, and the detector/injection valve etc. is installed on the top of the instrument. When maintaining/repairing the detector/valve, the frequent heating and cooling of the column can be avoided, which greatly improves the service life of the column.

3. application real column

Application example one:

PE samples, at concentrations of 2 mg/mL, 0.5 mg/mL, and 0.2 mg/mL, were injected in duplicate for each concentration. The results of the GPC-IR analysis are shown in Figure 1: We can see the GPC peaks at each concentration, with a stable baseline, good repeatability, and a good signal-to-noise ratio. In addition to the low concentration (0.2 mg/mL) of the sample, the IR5 detector also has a good response.

Fig.1 Results of GPC-IR analysis

Application example two:

GPC-IR analysis of bimodal low kilo-methyl HDPE: concentration 2 mg/ml, injection volume 200ul. The FTIR test requires liquid nitrogen and has many influencing factors, while the GPC-IR does not require liquid nitrogen and can directly obtain the short-chain branch information of the low-carbon methyl number sample, as shown in Figure 2.

Fig.2 GPC-IR analysis results of low kilocarbon methyl number HDPE pipe material

Application example three:

For the sample PE, the information of the long chain branch of the sample can be obtained GPC-IR the combination of multi-detector (viscosity detector and infrared detector). As shown in Figure 3, the further the deviation of the Mark's temperature curve of the sample from the linear standard, the more long chain branches. As shown in Figure 4, since GPC-IR can obtain the short chain branch information of the sample, we can obtain more accurate long chain branch information through short chain branch correction.

Fig.3 GPC-IR mark flood temperature curve of two detectors

Fig.4 Mark flood temperature curve corrected by short chain branch

Application example four:

Three PE samples are injected twice for each sample. Figure 5 below shows the IR5 original signals of the three samples. We can see that the baseline is stable and the repeatability is very good. At the same time, the concentration of the three samples is only 0.125 mg/mL, and the signal-to-noise ratio reaches 60, which can be directly quantitatively analyzed.

Fig.5 IR5 raw signal of three samples