Compatibility refers to the ability of each component of the blend to accommodate each other and form a macro uniform material.[1]
A large number of practical research results show that the capacity of mutual accommodation between different polymer pairs is very different.Some polymer pairs can have excellent compatibility;Other polymer pairs have limited compatibility;There are also some polymer pairs with little compatibility.Therefore, it can be divided into complete compatibility, partial compatibility and incompatibility according to the degree of compatibility.The corresponding polymer pairs can be called completely compatible system, partially compatible system and incompatible system respectively.[1]
n. Interchangeability;compatibility;Compatibility (coexistence, affinity, coordination, compatibility);adaptability
Phrase phrase
Electromagnetic compatibility
Incentive compatibility;Stimulus coordination
Adaptability test;Suitability test
example sentence
1. However, that’s not thecompatibilitywe’re talking about.
But that's not what we're talking aboutcompatibility。
2. This illustrates the applicationcompatibilitywith the new version.
This indicates the new version of the applicationcompatibility。
3. How can these positions be used in the debate on thecompatibilityof scienceand religion?
How can these positions be applied to scientific and religiouscompatibilityIn the debate?
Thermodynamics of polymer compatibility
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From a thermodynamic point of view,polymerThe compatibility between polymers isSolubility, refers to the ability of two polymers to form a homogeneous system.If the two polymers can form a homogeneous system at the molecular level in any proportion, they are completely compatible;Such as nitrocellulose polyacrylic acid methyl ester system.If two polymers can form stable homogeneous system only within a certain range of composition, they are partially compatible.If part of the compatibility is very small, it is incompatible, such aspolystyrene-polybutadieneSystem.
Compatibility depends on whether the change of free energy in the mixing process of the mixture is less than 0.That is, △ G=△ H-T △ S<0.For polymer mixing, because the molecular weight of the polymer is very large, the change of entropy during mixing is very small, and the polymer polymer mixing process is generally endothermic, that is, △ H is positive, so it is difficult to meet △ G<0.△ G is often positive, so most of the blended polymers cannot reach the molecular level of mixing, or are incompatible, forming heterogeneous systems.However, blend polymers can be compatible within a certain temperature range. Like polymer solutions, they have solubility curves, the highest critical compatibility temperature (UCST) and the lowest critical compatibility temperature (LCST), which are similar to the lowest boiling point and the highest boiling point of small molecule coexistence systems.Most polymer blends have the lowest critical compatibility temperature, which is an important feature of the compatibility between polymers.[3-4]
Fully compatible, partially compatible and incompatible
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The compatibility between polymer pairs can be reflected by the morphology of polymer blends.A completely compatible polymer blend system whose blends can form a homogeneous system.Therefore, the criterion of forming homogeneous system can also be used as the criterion of complete compatibility of polymer pairs.As mentioned above, if two polymers are blended, the resulting blend has a singleTg, it can be considered that the blend is a homogeneous system.Accordingly, if a polymer pair has a singleTg, it can also be considered that the polymer pair is completely compatible.
From the above description, it can be seen that "partial compatibility" is a very broad concept, which covers the compatibility of different degrees within the scope of two-phase systems.For partially compatible systems (two-phase systems), the advantages and disadvantages of compatibility are embodied in many aspects, such as the firmness of interface bonding, the difficulty of implementing blending, and the dispersion and uniformity of blending components.
For two-phase systems, people always want to have the best compatibility between their blending components.Good compatibility is an important prerequisite for polymer blends to obtain good properties.However, in practical applications, the compatibility of many polymer pairs is not ideal, and it is difficult to achieve the compatibility required for polymer modification through blending.Therefore, some measures need to be taken to improve the compatibility between polymer pairs.
The so-called compatibility refers to the mutual affinity when two or more substances are mixed, that is, the miscibility at the molecular level. Good compatibility can form a homogeneous mixed system.[1][3]
Use to determine theGlass transition temperatureTgThe method of comparing glass transition temperature with that of single component is the most commonly used method to measure and study the compatibility of blending components.
Schematic diagram of compatibility of blends characterized by Tg[3]
Generally, the dynamic mechanical property method can be used to measure the mechanical loss peak during the glass transition, as the characterization of 7.The relationship between the 7 peaks of the blend and the 8 peaks of the single component can have three basic situations, as shown in Figure 1.
The blends of partially compatible polymers are two-phase systems.The criterion of partial compatibility of polymer pair is that the blend of two polymers has twoTg, and twoTgThe peak is higher than that of each polymerTgThe peaks are closer together.In polymer blends, the most valuable system is two-phase system.Due to partially compatible polymers, their blends are two-phase systems. Accordingly, researchers have also paid more attention to partially compatible systems, which has become the focus of research.
There are also many polymer pairs that are incompatible.There are also two blends of incompatible polymersTgPeak, and twoTgThe position of the peak is the same as that of each polymerTgThe peaks are basically the same.
In addition to dynamic mechanical property testing methods, other methods that can be used to measure the glass transition temperature, such as DSC, can also be used to characterize the compatibility between the blend components.[5]
Infrared spectrometry
infrared spectrumThe method can also be used to study the compatibility of blending components.For the blend system with certain compatibility, the interaction between the components will make the infrared spectrum band of the blend deviate from that of a single component.The shift mainly occurs in the spectral band position of some groups.When hydrogen bonds are formed between the blend components, the shift will be more obvious.[5]
Electron microscopy
useelectron microscopeThe photos taken of the morphology of the blend can also be used to study the compatibility between the blend components.Generally speaking, when the compatibility between the blending components is good and a certain thickness of the boundary two transition layer is formed, the interface between the two phases is relatively fuzzy.
In addition, when the blending process is the same, the particle size of dispersed phase in the blend system with good compatibility is smaller.Electron microscopy can be combined with other characterization methods as an auxiliary characterization method of compatibility.[5]
Cloud point method
Polymer polymer isobaric phase diagram
The blends formed by two kinds of polymers can not be compatible with each other at any ratio and temperature.Some polymer pairs can only be completely compatible (forming a homogeneous system) within a certain range of ratio and temperature. Beyond this range, phase separation will occur and become a two-phase system.According to the difference of photographic separation temperature, it can be divided into two types: "low critical compatibility temperature" (LCST) and "high critical compatibility temperature" (UCST), as shown in Figure 2.
The relationship between the phase separation temperature of the blend and the composition in which phase separation occurs is called the phase diagram of the blend.The phase separation behavior represented by the phase diagram of blends can obviously be used to study the compatibility between the components of blends.
When the blend changes from a homogeneous system to a two-phase system, its light transmittance will change. This phase transition point is called the cloud point, and can be determined by measuring the cloud point.Cloud point method is commonly used in the theoretical study of compatibility.[5]
Reversed phase chromatography
Reversed phase chromatography was used to study the compatibility of blends, and its method was also to determine the phase separation behavior of the blend components.
Reverse phase chromatography uses a small molecule as a "probe molecule" to determine the retention volume of the system（Vg）。When phase separation occurs in the blend, the retention mechanism of the probe molecule changes, makinglgVg-1/TDeviation from a straight line.The inflection point is where the phase change occurs in the blend system.For some blend components with similar refractive index, which cannot be measured by cloud point method, the phase separation behavior can be measured by reverse phase chromatography.[5]
Good compatibility meansadditive(e.gsolvent、PlasticizerIt can exist in the system for a long time, stably and evenly.Poor compatibility, liquidresinWill appearStratification phenomenon。PlasticIf the precipitate of the product is solid, it is called“Frost spraying”, in case of liquid, called“sweat”, which affects the product quality and appearance.
When bothhigh polymerThe interaction energy between molecules is greater than that between their respective moleculesInteraction energyWhen,blendCan emit heat, then these two polymersthermodynamicsIt is completely compatible on the contrary.Experiments have proved that the vast majorityrubberblendWhen isendothermicOf, orMixed thermal effectClose to zero, incompatible, only a fewhigh polymerMixing is an exception, such asNatural rubberAndHigh styrene resin、Carboxyl containing rubberandVinyl pyridine rubberMixing is exothermic.Generally speaking, thesolubilityThe closer the parameters are, the better their compatibility is.
Biology
It refers to a concept of various biological, physical, chemical and other reactions generated by the interaction between materials and organisms.Generally speaking, it refers to the degree of compatibility between the material and the human body after it is implanted into the human body, that is, whether it will cause toxic effects on human tissues.
mathematics
mathematicsIn the formalLogical systemThe compatibility means that there is nocontradictionOr more precisely, there is no proposition P, and both P and non P can be proved in this system.
Compatibility in data means that two data representing the same fact should be the same, otherwise they will be incompatible or a group of data meeting a constraint relationship should not be mutually exclusive, otherwise they will be incompatible.For example, the same person cannot have two genders;When inputting the feed ratio, the sum of the percentages of several raw materials should be equal to 100%, but it is incompatible if the sum is not equal to 100%.
Architecture
When the adhesive seal material contacts with other materials, the performance of physical and chemical changes that will not affect the adhesive property of the adhesive seal material will not occur.
