差示扫描热量仪
发布时间: 2017-12-15 浏览次数: 82

DSC 操作说明

目 录

•关于样品

•特别提示

•样品准备

•开机准备

•程序设置

•程序运行

•数据分析

•数据导出

•整理

关于样品

•样品预先按照正确方法处理好,如:

–去除不需要的水分

–玻璃化温度测定前,稳定24小时

–形态尽量为粉末状

•样品有无爆炸性需特别注意!

–不做爆炸性物,及含能粒子物,如ClO4-

–不清楚时需预先检验,如少量样品烧灼或锤击

特别提示

•样品台及温度探头勿受金属等硬物刮擦!

•温度高限不能超过仪器限制,如500℃!

•除非十分必要,不做分解温度测试。

•仪器运行中须经常检视

•热物件放置右侧黑色平台上

耐热平台

样品准备

•准确称量3-10mg,放置坩埚底部使成薄层

•放上埚盖,以镊子轻压,再转移至压盖器

•分多次轻轻试压,将埚盖压紧至最低位置

•最终坩埚底部不变形、呈平面!

坩埚

坩埚盖

压盖器

开机准备

•打开稳压器及仪器电源开关

•开启气体钢瓶总阀,调出口压0.05MPa

•点击TA Instrument Explorer,等出现仪器界面后,再点击其图标,出现操作界面

①仪器图标

②仪器启动后界面

③操作界面

程序设置

•将压好的样品埚置样品平台上(靠自己一方)

•按由里到外顺序盖好三个盖子

•在软件界面实验视窗中,输入有关信息:

•Summary的填写:

– Procedure summary 中→选择standard; custom

–Sample中→输入样品名称; 质量

–Data file name中→建立个人数据的位置

点Summary

点Procedure

点Notes

•Procedure的填写:

–Procedure information中 →选custom;其它

–Method [1]:

•编写方法:点击Editor,删除原有语句,双击右侧segment list中合适命令组织方法,点击各命令的数字,激活后填写预定数据,如实验开始温度、稳定时间、加热速率及实验结束温度等,核查无误。

•选择现成的方法(除Custom外的其它方法)

Notes的填写:氮气流量20(-50) ml/min

典型的升温程序

程序运行

•点击左上侧图标,开始运行。

•程序运行中,右下侧视窗实时显示热流变化。

•设定程序完成后,运行自动终止,停止升温

•点击左上侧图标,可随时终止运行。

•程序结束后,在菜单栏control中,点击stop。

数据分析

•点击图标 TA universal analysis,打开数据分析界面。

•点击界面上方的分析模式,进行分析。

–可先用鼠标画框,选定相关区域,放大后进行

•峰面积计算

–要根据相关知识,选择合适的基线种类再积分,如线形、曲线等。

–调整积分前后两个端点到适当位置

–在空白区右击鼠标,选择accept limits,得结果

数据导出

•打开一个数据文件

–菜单 file 中,找到 export data file,选择需要的数据如 file signals only

–在弹出的界面里,选择文件格式与字符类型,如 spreadsheettext file、OEM。

–点击 finish 完成最终导出

整理

•将天平、压盖器、镊子、样品勺等物品清理干净。

•将坩埚收好

•等温度降至室温,可关闭电源及气体,结束实验。

附录

•关于加热程序编写方法的说明

(1)自己编写即custom的方法,需要熟悉各种命令的意义,请参见附件segment list.

(2)选用预先编好的程序,即下拉菜单中除custom以外的方法,使用时一定要参照附件segment list。

(3)实验中一些具体的细节听熟悉的人指导。

附segment list

A segment is a preprogrammed series of instructions usedin a method. Several segments can be linked together to create the desiredmethod. The available segment list will vary depending on the instrument andoptional accessories installed.

For details on a specificsegment see the table below:

Segment

Description

Abort next segment on limit

Available for DSC,TGA, and SDT Only:  The Abort next  segment on limit segment allows you to skip over or terminate other method  segments when specified limit conditions are met. Then the experiment  proceeds to the next segment.

  • If the limit is       reached at the beginning of a segment, then that segment is skipped and       method execution continues with the next segment.

  • If the limit is       reached during the execution of a segment, then the remaining portion of       the segment is skipped.

NOTE: The Abort segment is  generally followed by a Ramp, or Isothermal segment.

Example (DSC):

  1. Equilibrate at 200°C

  2. Abort next       segment if mW>1

  3. Isothermal for       100 min

Abort next segment on signal

Available for DMA and TMA Only:  The Abort next  segment on signal segment allows you to skip over or terminate other method  segments when specified limit conditions are met. Then the experiment  proceeds to the next segment. The signal specified for limit checking can be  any signal that is being saved into the datafile.

  • If the limit is       reached at the beginning of a segment, then that segment is skipped and       method execution continues with the next segment.

  • If the limit is       reached during the execution of a segment, then the remaining portion of       the segment is skipped.

Example (DMA):

  1. Equilibrate at 100°C

  2. Abort next       segment if Storage Modulus < 1000 Mpa

  3. Ramp 5°C/min to 200°C

  4. Isothermal for       10 min

  5. Ramp 5°C/min to 100°C

Air Cool

Available for DSC Only:  The Air Cool segment  controls the internal cooling solenoid valve connected to compressed air (air  cool feature). Air cool activates when the furnace is below 600°C.

Example:  Air Cool: On

Data storage

The Data storage segment controls data collection  during the experiment. If a Data Storage segment is not used, data storage  will be automatically initiated by the first Ramp, Isothermal, or Step  segment that appears in the method.

Example: Data Storage: On

Equilibrate

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The Equilibrate segment heats or cools the furnace to  the defined temperature, stabilizes the furnace at that temperature, then  continues to the next segment. This segment does not automatically start data  collection.

Example: Equilibrate at 200°C

External Event

The Event segment controls the external event relay  through the event jack on the back of the instrument. This is used to  synchronize control of additional hardware through the method.

Example: External Event: On

Fill Cooler

Available for DMA and DSC Only:  This segment is used  to control the filling of the Gas Cooling Accessory (GCA) or Liquid Nitrogen  Cooling System (LNCS) when it falls below an entered percentage during an  experiment.

Example:  Fill Cooler if below 50%

Flow Rate

Available for MFC Only:  The Flow Rate  segment is used to alter the rate of flow of the selected gas when an  instrument is equipped with a Mass Flow Controller.

Example:  Flow rate 50 mL/min

Force

Available for DMA Only:  The Force segment  applies a constant static force to the sample, then executes the next  segment. This segment is only valid for experiments done in the Controlled  Force and Strain Rate modes.

The Force segment in the Strain Rate mode shuts off  displacement (strain) control when this segment is executed. Executing a  subsequent Set Strain or Ramp Strain segment shuts off force control and  resumes displacement (strain) control.

Example:  Force 0.5 N

Frequency Sweep

Available for DMA Only:  The Frequency Sweep  segment is used in multiple frequency experiments to collect data at each  frequency in the selected frequency table at a constant temperature. This  segment is only valid for DMA Multifrequency mode.

This segment turns on data storage when it begins, and  turns it off when it ends.

Gas Selection

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Available with the MFC Only:  The Gas segment  controls the switching of gas, between Gas 1 and Gas 2 for an instrument with  a Mass Flow Controller (MFC) installed. This segment is used to synchronize  gas switching at a specific time or temperature in an experiment.

Example: Select Gas1

Heater PID

The Heater PID segment is used to change the  performance of the instrument furnace during the execution of a thermal  method. PID stands for Proportional, Integral, and Derivative, the three  modes of traditional temperature control. The Heater PID segment specifies  the control coefficients for each mode of temperature control.

For more detailed information, click here more.

Example: P= 35  I= 70 D=2

High Resolution ramp

Available for TGA High Resolution instruments only. The High Resolution  ramp segment varies the heating/cooling rate of the furnace in response to  changes in the rate of decomposition of the sample to improve weight change  resolution.

Example: Ramp 50.00°C/min  res 4.0 to 800.00°C

High Resolution sensitivity

Available for TGA High Resolution instruments only. The High Resolution  sensitivity segment sets an additional parameter associated with the High  Resolution ramp segments, which can be used to adjust the response of the  High Resolution temperature control algorithm. This is sometimes necessary  due to the wide variation in decomposition mechanisms of typical sample  materials. The sensitivity setting is a unitless number ranging from 1.0  (lowest sensitivity) to 8.0 (highest sensitivity). Increasing sensitivity  tends to increase experiment time.

Example: High resolution sensitivity 2.0

Increment Force

Available for DMA Only:  The Increment Force  segment raises or lowers the static force in a step, then executes the next  segment. This segment is only valid for experiments done in controlled force  mode.

Example:

1. Equilibrate to 50°C

2. Isothermal for 5 min.

3. Increment force 0.05 N

4. Repeat segment 2 for 3 times

Increment Temperature

The Increment Temperature segment raises or lowers the  temperature in a controlled step, lets the temperature equilibrate, then  begins the next segment.

Example: Increment by 5°C

Initial temperature

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The Initial Temperature segment heats or cools the  furnace to the defined temperature, stabilizes the furnace at that  temperature, then holds the temperature until the experiment is continued by  selecting Resume on the Tool Bar or menu, or pressing START on the instrument  keypad. The instrument status will display ready when the  temperature is stabilized. This segment does not automatically start data  collection.

Example: Initial Temp 200°C

Isostrain

Available for DMA Only:  The Isostrain  segment applies an instantaneous strain to the sample and the force required  to maintain the strain at a constant value is monitored.

Example:

1. Equilibrate 30°C

2. Isostrain at 1%

3. Ramp 3°C/min  to 200°C

Isothermal

The Isothermal segment holds the sample at the current  temperature (as programmed by the previous segment) for a defined period of  time. This segment automatically turns on data collection, except when  preceded by a Data Storage OFF segment.

Example: Isothermal for 10 min

Jump

The Jump segment instantly changes the set point  temperature, causing ballistic changes in the sample temperature. This  segment then allows the immediate execution of the next segment (which is  usually the Isothermal segment). Note that large temperature overshoots may  result from the use of this segment. This segment does not automatically  start data collection.

Example: Jump to 200°C

Mark end of cycle

The Mark end of cycle segment places a marker in the  data for use by the data analysis programs. In general markers provide quick  parsing of data to separate experimental segments (i.e., the heat-cool  cycle). A cycle mark number of 0 will automatically increment the mark number  each time it is used, providing a running cycle count.

Example: Mark end of cycle 0

Modulate temperature

Available for Modulated Instruments Only: This segment allows  you to enter the peak modulation temperature amplitude and period (frequency)  parameters that will be used with subsequent ramp or isothermal segments.

Example: Modulate +5.00 °C every 200 seconds

Motor drive

Available for DMA Only:  The Motor Drive  segment is used to automatically turn the drive motor on and off during an  experiment. The motor will automatically start when the experiment is  started, unless you select Motor Drive off as the first segment in a method.

Ramp

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The Ramp segment heats or cools the sample at a fixed rate  until it reaches the specified temperature, producing a linear plot of  temperature versus time. This segment automatically turns on data collection,  except when preceded by a Data Storage OFF segment.

Example: Ramp 10°C/min  to 200°C

Ramp Displacement

Available for DMA Only:  This segment ramps  the displacement setpoint linearly with time to a final strain value. Only  available in the strain rate mode.

Ramp Force

Available for DMA Only:  The Ramp Force  segment raises or lowers the force at a fixed rate until a final force is  reached, while the sample is held at a constant temperature. This segment is  only valid for experiments done in the controlled force mode.

Example: Ramp force 0.2 N/min to 1.0 N

Ramp Strain

Available for DMA Only:  This segment ramps  the strain setpoint linearly with time to a final strain value. Only  available in the strain rate mode.

Repeat

The Repeat segment does exactly what the name implies,  it repeats a group of one or more segments within a method for the number of  times specified.

Example:

  1. Ramp 5°C/min to 200°C

  2. Ramp 5°C/min to 50°C

  3. Repeat segment 1 for 2       times

Repeat Until

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The Repeat Until segment repeats of group of one or  more segments within a method until the specified final temperature is  reached or passed.

Example:

  1. Equilibrate at 50°C

  2. Isothermal for 5 min

  3. Increment 10°C

  4. Repeat segment 2 until 200°C

Sample interval

The Sample interval segment allows you to define or  change the rate at which data is to be collected (in seconds/point).

Example: Sampling interval 0.2 sec/pt

Set Strain

Available for DMA Only:  Allows you to change  the strain setpoint during experiments run in the stress relaxation,  isostrain, and strain rate modes.

Step

The Step segment causes the temperature to jump a  specified number of degrees at a specified time interval until a final  temperature is reached. This segment automatically turns on data collection,  except when preceded by a Data Storage OFF segment.

Example: Step 5°C  for 2 min to 200°C

Strain Sweep

Available for DMA Only:  The Strain Sweep  segment is used in multiple amplitude experiments to collect data at each  amplitude in the selected amplitude table at a constant temperature. This  segment is only valid for the DMA Multistrain mode.

This segment turns on data storage when it begins, and  turns it off when it ends.

Zero Heat Flow

Available for DSC: The Zero Heat Flow segment sets  the absolute value of the heat flow signal to zero at the end of a  five-minute isothermal period. This ensures that the heat flow signal is  accurate, which is important for obtaining accurate total heat capacity  signals.

Example: Zero heat flow at 50°C.