差示扫描量热法测定ABS的氧化诱导温度

采用差示扫描量热法（DSC）测定ABS的氧化诱导温度，来评价ABS的热氧化稳定性；并结合热分析工作的实际经验提出了使用氧化诱导温度测试方法需注意的问题。方法简单快速，重复性好，相对标准偏差小于5％。     

差示扫描量热法测定固体催化剂比热

DSC法测定物质的比热,方法简便、快速,试样量少。用标准物质蓝宝石校正仪器在76.8～506.8℃区域内的仪器常数。应用DSC法测定了数种固体催化剂及其载体的比热值,并用杜邦公司提供的比热分析软件标绘比热-温度关系曲线。用该法测量J型催化剂平均比热为918J/kg·℃的重复性表明,标准偏差为12.14,相对标准偏差为1.3%。     

喷气燃料冰点的差示扫描量热法测定

介绍差示扫描量热法(DSC)测定喷气燃料冰点的原理和实验过程。用DSC法测定了不同型号的8种喷气燃料的冰点,测定结果与国标法GB/T 2430-1981测定的一致。     

差示扫描量热法测定塑料的氧化诱导时间和氧化诱导温度

修改采用ISO 11357:2008《塑料—差示扫描量热法(DSC)第6部分:氧化诱导时间(等温OIT)和氧化诱导温度(动态OIT)的测定》,制定我国相应的国家标准GB/T 19466.6-2009。国内共有13个主要的塑料产品生产厂家和科研单位参加了标准的制定和验证试验工作。该标准的制定填补了我国采用DSC法测定塑料氧化诱导时间(等温OIT)和氧化诱导温度(动态OIT)的空白。     

差示扫描量热法测定防老剂4020的纯度

研究差示扫描量热（DSC）法测定防老剂4020的纯度。确定的测试条件如下：取样量　2～3 mg,升温速率　0.7 ℃·min-1,保护气体流速　20～40 mL·min-1。试验表明DSC法测定防老剂4020的纯度与常规气相色谱法测定结果很接近,同时该方法操作简单、用时短,对环境友好。     

聚酯的差示扫描量热法热性能分析

使用DSC差示扫描量热仪分析了三种聚酯产品的热性能。同等试样量时,从测得试样的熔点、结晶度及曲线图形可以分析判断出,PET-2聚酯样品产品质量最好。     

差示扫描量热法测定合成树脂乳液玻璃化转变温度的研究

本研究通过真空干燥法将合成树脂乳液中溶剂除去,利用差示扫描量热法测定树脂乳液玻璃化转变温度,对测定过程的影响因素进行分析,选出了针对合成树脂乳液特性的前处理方法及测定方法。并对方法的重复性及再现性进行了计算,相对重复性≤1%,相对再现性≤1%。该方法操作简单,重复性、再现性较高,为检测合成树脂乳液玻璃化转变温度提供了理论依据,同时为企业原材料监管提供了简便、稳定的测试方法。     

温度调制式差示扫描量热法及其应用

介绍一种新的热分析方法一温度调制式差示扫描量热法(TMDSC)。它与差示扫描量热法(DSC)相比，可以获得更多的信息。该方法可应用于高分子材料，无机与有机以及药物与食品科学等领域。     

差示扫描量热法测定聚丙烯腈纤维玻璃化转变温度

本文采用差示扫描量热法,两段升温模式,以10℃/min加热速度,从30℃加热到150℃,测定了4个聚丙烯腈纤维样品的玻璃化转变温度,探讨了加热方法和样品量试验条件,得到了准确可靠的玻璃化转变温度。     

氧化诱导期法评价聚烯烃管材的抗热氧稳定性

采用氧化诱导期（OIT）法探讨了聚烯烃管材在加工过程中的降解反应及其影响因素，对交联聚乙烯管材进行4点温度OIT测试，并分析在所拟合的直线方程中与抗氧剂损耗活性相关的斜率对热氧稳定性的影响，同时外推使用温度下的热氧寿命，并以95℃热水浸泡后200℃时的OIT保留率作为辅助手段，找出内在关联，建立评价方法。     

Analysis of the induction period of oxidation of edible oils by differential scanning calorimetry

Oxidation of rapeseed and sunflower oils has been studied by differential scanning calorimetry under non-isothermal conditions and by Oxidograph under isothermal conditions for various temperatures. The parameters of an Arrhenius-like equation describing the temperature dependence of induction period have been obtained. A new method for evaluation of the parameters from nonisothermal diffential scanning calorimetry measurements, based on the dependence of onset temperature of the oxidation peak on heating rate, is presented. It has been shown that the method gives parameters not affected by systematic errors. These can be used in modeling the oxidation process where the effects of oxygen diffusion, heat transfer, and evolution of reaction heat are explicity involved. The results obtained by differential scanning calorimetry are compared with the Oxidograph measurements. The discrepancies between the results obtained by the two methods are accounted for by oxygen diffusion within the samples.     

Differential scanning calorimetry of hydrolysed mangrove tannin

Mangrove‐bark‐tannin adhesives are potential substitutes for phenol–formaldehyde (PF) wood‐bonding adhesives which are derived from petroleum, a finite natural resource. However, mangrove‐bark‐tannin adhesive exhibits poor adhesive properties, including brittleness, poor wet strength, and poor wood penetration. These shortcomings are due to its high reactivity and structural features. To reduce these shortcomings, the structure of the adhesive was modified by subjecting tannin to (a) caustic hydrolysis and (b) consecutive acetic anhydride and caustic hydrolysis. The effectiveness of these hydrolyses was determined by using differential scanning calorimetry (DSC) to monitor the reaction and cure characteristics of hydrolysed and unhydrolysed tannin with formaldehyde. These hydrolyses resulted in lowering both the activation energy and collision frequency of the cure reaction. Consequently, the initial reactivity of tannin towards paraformaldehyde, which was usually very high, was reduced. The resulting longer reaction time enhanced the extent of reaction, as was evident in the increase in heat of reaction of the hydrolysed tannin. © 2000 Society of Chemical Industry     

Differential scanning calorimetry of crystallized PVA hydrogels

Crosslinked poly(vinyl alcohol) hydrogels produced via electron beam irradiation of aqueous PVA solutions were crystallized via a two-stage dehydration-annealing process to produce swollen hydrogels of varying degrees of crystallinity. Evaluation of the degree of crystallinity of these hydrogels was done by differential scanning calorimetry (DSC) analysis. The swollen hydrogels had degrees of crystallinities varying between 30% and 50% depending on the temperature–time history of the specimens.     

Differential scanning calorimetry of palm kernel oil products

A variety of fractionated and hydrogenated fats were derived from a commercial sample of Malayan palm kernel oil. These were studied by differential scanning calorimetry at different rates of cooling and heating. The resulting thermograms, and latent heats derived from them, were compared with one another and with underlying triglyceride compositions. This enabled three potential interpretations of the thermograms to be compared. The shapes of the cooling thermograms were most complicated, and dependent on the influence of the spontaneous crystallization, which followed supercooling when cooling rates of 8 C per min or more were imposed. Triglyceride composition had a less significant influence on the shapes of the curves, while polymorphism had almost no influence. The cooling thermograms, thus, are more complicated than heating thermograms, a conclusion at variance with one expressed elsewhere. The dynamic nature of the differential scanning calorimetry method is highlighted by the results of this work, and it is concluded that there are dangers in conducting differential scanning calorimetry studies at a single rate of temperature change.     

Differential scanning calorimetry of the epoxy cure reaction

From a review of the literature it is shown that kinetics from programmed heating rate experiments are often in serious disagreement with published isothermal data. In every case, including the present, the dynamic kinetic parameters measured on epoxies are significantly larger than the isothermal. Use of a dynamic rate equation provides good agreement between the two experiments. It is also shown that the Kissinger method is correct when applied to DSC of epoxies.     

Differential scanning calorimetry investigation of curing of bisphenolfurfural resins

Bisphenolic resins have been prepared by alkali catalyzed condensation of bisphenol-F, bisphenol-A, and bisphenol-C, respectively, with furfural. The resin samples have been characterized by elemental analysis, dilute solution viscosity measurement, and measurement of number-average molecular weight. Curing reactions of these bisphenolic resins with hexamine have been investigated by differential scanning calorimetry. The overall apparent activation energies for the curing have been found to be 24 ± 2, 34.2 ± 1.9, and 36.8 ± 2.3 kcal/mole for bisphenol-F-furfural, bisphenol-A-furfural, and bisphenol-C-furfural resin, respectively. The curing reactions have been found to follow an overall first-order kinetics.     

Differential scanning calorimetry of aqueous polymer solutions and gels

The melting phenomena of aqueous polymer solutions and gels have been investigated by differential scanning calorimetry (DSC). The polymers used were synthetic polyacrylamide and poly(vinyl alcohol) samples as well as guar and xanthan gums. By using an empirical relation, the energy measured from the area under the melting peak yielded heats of mixing and sorption, when fitted by an association factor computed from the data. This factor (independent of the concentration) is a measure of the water fraction associated with the polymer and has a definite and characteristic value for a given polymer in water. When a crosslinking agent (potassium pyroantimoniate or chromic nitrate) was added to the water–polymer system, the association factor varied with the polymer concentration; the macromolecular chains thus become less accessible to penetrating water. If a branched gel was obtained owing to the formation of chemical crosslinks, a hump appeared on the melting peak.     

Differential scanning calorimetry of phenol–formaldehyde resols

Differential scanning calorimetry was used on a range of synthesized phenol–formaldehyde (PF) resols to discover relationships between formulation parameters or physical properties of resols, and their thermal behavior during cure. The thermograms showed either one or two exothermic reactions. The lower exothermic peak temperature varied between 98 and 129°C with changes in the free formaldehyde content. This exotherm is caused by the addition of free formaldehyde to phenolic rings. The upper exothermic peak temperature varied from 139 to 151°C, with the higher temperatures occurring when the formaldehyde-to-phenol molar ratio was low or the total amount of sodium hydroxide relative to phenol was high. These two factors led to resins which contain a somewhat higher level of unreacted ortho or para aromatic ring positions and no free formaldehyde. Consequently, condensation is probably not solely by the faster self-condensation through hydroxymethyl groups, but also includes the slower condensation of hydroxymethyl groups with unreacted ring positions. Gel times show trends with changes of formulation parameters somewhat similar to trends of the upper exothermic peak temperatures.